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EXTRACLANGTOOLS(1)	       Extra Clang Tools	    EXTRACLANGTOOLS(1)

NAME
       extraclangtools - Extra Clang Tools Documentation

       Welcome	to  the	 clang-tools-extra  project which contains extra tools
       built using Clang's tooling APIs.

EXTRA CLANG TOOLS 9.0.0	RELEASE	NOTES
       o Introduction

       o What's	New in Extra Clang Tools 9.0.0?

	 o Improvements	to clangd

	 o Improvements	to clang-tidy

	 o Improvements	to pp-trace

       Written by the LLVM Team

   Introduction
       This document contains the release notes	for  the  Extra	 Clang	Tools,
       part of the Clang release 9.0.0.	Here we	describe the status of the Ex-
       tra Clang Tools in some detail, including major improvements  from  the
       previous	 release  and new feature work.	All LLVM releases may be down-
       loaded from the LLVM releases web site.

       For more	information about Clang	or LLVM, including  information	 about
       the latest release, please see the Clang	Web Site or the	LLVM Web Site.

   What's New in Extra Clang Tools 9.0.0?
       Some  of	 the  major new	features and improvements to Extra Clang Tools
       are listed here.	Generic	improvements to	Extra Clang Tools as  a	 whole
       or  to  its  underlying infrastructure are described first, followed by
       tool-specific sections.

   Improvements	to clangd
       o Background indexing is	on by default

	 When using clangd, it will build an index  of	your  code  base  (all
	 files listed in your compile database). This index enables go-to-def-
	 inition, find-references, and even code completion  to	 find  symbols
	 across	your project.

	 This  feature	can consume a lot of CPU. It can be disabled using the
	 --background-index=false flag,	and respects -j	to use fewer  threads.
	 The index is written to .clangd/index in the project root.

       o Contextual code actions

	 Extract  variable,  expand  auto, expand macro, convert string	to raw
	 string.  More to come in the future!

       o Clang-tidy warnings are available

	 These will be produced	for projects that have a .clang-tidy  file  in
	 their source tree, as described in the	clang-tidy documentation.

       o Improved diagnostics

	 Errors	from headers are now shown (on the #including line).  The mes-
	 sage now indicates if fixes are available.  Navigation	between	errors
	 and  associated  notes	is improved (for editors that support Diagnos-
	 tic.relatedInformation).

       o Suggested includes

	 When a	class or other name is not found, clangd may  suggest  to  fix
	 this by adding	the corresponding #include directive.

       o Semantic highlighting

	 clangd	 can  push  syntax  information	 to the	editor,	allowing it to
	 highlight e.g.	member variables differently  from  locals.  (requires
	 editor	support)

	 This	    implements	     the      proposed	    protocol	  from
	 https://github.com/microsoft/vscode-languageserver-node/pull/367

       o Type hierachy

	 Navigation to base/derived types is possible in editors that  support
	 the		    proposed		   protocol		  from
	 https://github.com/microsoft/vscode-languageserver-node/pull/426

       o Improvements to include insertion

	 Only headers with #include-guards will	be inserted, and  the  feature
	 can be	disabled with the --header-insertion=never flag.

	 Standard library headers should now be	inserted more accurately, par-
	 ticularly for C++ other than libstdc++, and for the  C	 standard  li-
	 brary.

       o Code completion

	 Overloads  are	bundled	into a single completion item by default. (for
	 editors that support signature-help).

	 Redundant const/non-const overloads are no longer shown.

	 Before	clangd is warmed up (during preamble build),  limited  identi-
	 fier- and index-based code completion is available.

       o Format-on-type

	 A new implementation of format-on-type	is triggered by	hitting	enter:
	 it attempts to	reformat the previous line and reindent	the new	 line.
	 (Requires editor support).

       o Toolchain header detection

	 Projects  that	 use an	embedded gcc toolchain may only	work when used
	 with the corresponding	standard library. clangd  can  now  query  the
	 toolchain  to find these headers.  The	compilation database must cor-
	 rectly	      specify	    this       toolchain,	and	   the
	 --query-driver=/path/to/toolchain/bin/*   flag	  must	be  passed  to
	 clangd.

       o Miscellaneous improvements

	 Hover now produces richer Markdown-formatted text (for	supported edi-
	 tors).

	 Rename	 is  safer  and	 more helpful, though is still within one file
	 only.

	 Files without extensions (e.g.	C++ standard library) are handled bet-
	 ter.

	 clangd	can understand offsets in UTF-8	or UTF-32 through command-line
	 flags or protocol extensions.	(Useful	 with  editors/platforms  that
	 don't speak UTF-16).

	 Editors that support edits near the cursor in code-completion can set
	 the textDocument.completion.editsNearCursor capability	to  true,  and
	 clangd	will provide completions that correct .	to ->, and vice-versa.

   Improvements	to clang-tidy
       o New OpenMP module.

	 For checks specific to	OpenMP API.

       o New abseil-duration-addition check.

	 Checks	for cases where	addition should	be performed in	the absl::Time
	 domain.

       o New abseil-duration-conversion-cast check.

	 Checks	for casts of absl::Duration conversion functions,  and	recom-
	 mends the right conversion function instead.

       o New abseil-duration-unnecessary-conversion check.

	 Finds and fixes cases where absl::Duration values are being converted
	 to numeric types and back again.

       o New abseil-time-comparison check.

	 Prefer	comparisons in the absl::Time domain instead  of  the  integer
	 domain.

       o New abseil-time-subtraction check.

	 Finds	and fixes absl::Time subtraction expressions to	do subtraction
	 in the	Time domain instead of the numeric domain.

       o New android-cloexec-pipe check.

	 This check detects usage of pipe().

       o New android-cloexec-pipe2 check.

	 This checks ensures that pipe2() is called with the O_CLOEXEC flag.

       o New bugprone-branch-clone check.

	 Checks	for repeated branches in if/else if/else  chains,  consecutive
	 repeated  branches in switch statements and indentical	true and false
	 branches in conditional operators.

       o New bugprone-posix-return check.

	 Checks	if any calls to	POSIX functions	(except	 posix_openpt)	expect
	 negative return values.

       o New bugprone-unhandled-self-assignment	check.

	 Finds user-defined copy assignment operators which do not protect the
	 code against self-assignment either by	checking  self-assignment  ex-
	 plicitly or using the copy-and-swap or	the copy-and-move method.

       o New fuchsia-default-arguments-calls check.

	 Warns if a function or	method is called with default arguments.  This
	 was previously	done by	 fuchsia-default-arguments  check,  which  has
	 been removed.

       o New fuchsia-default-arguments-declarations check.

	 Warns	if  a  function	or method is declared with default parameters.
	 This was previously done by  fuchsia-default-arguments	 check	check,
	 which has been	removed.

       o New google-objc-avoid-nsobject-new check.

	 Checks	 for calls to +new or overrides	of it, which are prohibited by
	 the Google Objective-C	style guide.

       o New google-readability-avoid-underscore-in-googletest-name check.

	 Checks	whether	there are underscores in googletest test and test case
	 names in test macros, which is	prohibited by the Googletest FAQ.

       o New llvm-prefer-isa-or-dyn-cast-in-conditionals check.

	 Looks	at  conditionals and finds and replaces	cases of cast<>, which
	 will assert rather than return	a null pointer,	and  dyn_cast<>	 where
	 the  return  value  is	not captured. Additionally, finds and replaces
	 cases that match the pattern var && isa<X>(var), where	var is	evalu-
	 ated twice.

       o New modernize-use-trailing-return-type	check.

	 Rewrites function signatures to use a trailing	return type.

       o New objc-super-self check.

	 Finds invocations of -self on super instances in initializers of sub-
	 classes of NSObject and recommends calling a  superclass  initializer
	 instead.

       o New openmp-exception-escape check.

	 Analyzes  OpenMP  Structured  Blocks and checks that no exception es-
	 capes out of the Structured Block it was thrown in.

       o New openmp-use-default-none check.

	 Finds OpenMP directives that are allowed to contain a default clause,
	 but  either  don't specify it or the clause is	specified but with the
	 kind other than none, and suggests to use the default(none) clause.

       o New readability-convert-member-functions-to-static check.

	 Finds non-static member functions that	can be made static.

       o New alias cert-oop54-cpp  to  bugprone-unhandled-self-assignment  was
	 added.

       o New  alias  cppcoreguidelines-explicit-virtual-functions  to  modern-
	 ize-use-override was added.

       o The bugprone-argument-comment now supports CommentBoolLiterals,  Com-
	 mentIntegerLiterals,  CommentFloatLiterals, CommentUserDefiniedLiter-
	 als, CommentStringLiterals, CommentCharacterLiterals &	 CommentNullP-
	 trs options.

       o The bugprone-too-small-loop-variable now supports MagnitudeBitsUpper-
	 Limit option. The default value was set to 16,	which greatly  reduces
	 warnings related to loops which are unlikely to cause an actual func-
	 tional	bug.

       o Added UseAssignment option to cppcoreguidelines-pro-type-member-init

	 If set	to true, the check will	provide	fix-its	with literal  initial-
	 izers (int i =	0;) instead of curly braces (int i{};).

       o The fuchsia-default-arguments check has been removed.

	 Warnings  of  function	 or method calls and declarations with default
	 arguments were	moved  to  fuchsia-default-arguments-calls  and	 fuch-
	 sia-default-arguments-declarations checks respectively.

       o The google-runtime-int	check has been disabled	in Objective-C++.

       o The  modernize-use-override  now supports OverrideSpelling and	Final-
	 Spelling options.

       o The  misc-throw-by-value-catch-by-reference  now   supports   WarnOn-
	 LargeObject  and  MaxSize options to warn on any large	trivial	object
	 caught	by value.

       o The Acronyms and IncludeDefaultAcronyms options  for  the  objc-prop-
	 erty-declaration check	have been removed.

   Improvements	to pp-trace
       o Added	a  new	option -callbacks to filter preprocessor callbacks. It
	 replaces the -ignore option.

CLANG-TIDY
   Contents
       o Clang-Tidy

	 o Using clang-tidy

	 o Suppressing Undesired Diagnostics

       See also:

   Clang-Tidy Checks
   abseil-duration-addition
       Check for cases where addition should be	performed  in  the  absl::Time
       domain.	 When adding two values, and one is known to be	an absl::Time,
       we can infer that the other should be interpreted as an	absl::Duration
       of a similar scale, and make that inference explicit.

       Examples:

	  // Original -	Addition in the	integer	domain
	  int x;
	  absl::Time t;
	  int result = absl::ToUnixSeconds(t) +	x;

	  // Suggestion	- Addition in the absl::Time domain
	  int result = absl::ToUnixSeconds(t + absl::Seconds(x));

   abseil-duration-comparison
       Checks for comparisons which should be in the absl::Duration domain in-
       stead of	the floating point or integer domains.

       N.B.: In	cases where a Duration was being converted to an  integer  and
       then compared against a floating-point value, truncation	during the Du-
       ration conversion might yield a different result. In practice  this  is
       very rare, and still indicates a	bug which should be fixed.

       Examples:

	  // Original -	Comparison in the floating point domain
	  double x;
	  absl::Duration d;
	  if (x	< absl::ToDoubleSeconds(d)) ...

	  // Suggested - Compare in the	absl::Duration domain instead
	  if (absl::Seconds(x) < d) ...

	  // Original -	Comparison in the integer domain
	  int x;
	  absl::Duration d;
	  if (x	< absl::ToInt64Microseconds(d))	...

	  // Suggested - Compare in the	absl::Duration domain instead
	  if (absl::Microseconds(x) < d) ...

   abseil-duration-conversion-cast
       Checks for casts	of absl::Duration conversion functions,	and recommends
       the right conversion function instead.

       Examples:

	  // Original -	Cast from a double to an integer
	  absl::Duration d;
	  int i	= static_cast<int>(absl::ToDoubleSeconds(d));

	  // Suggested - Use the integer conversion function directly.
	  int i	= absl::ToInt64Seconds(d);

	  // Original -	Cast from a double to an integer
	  absl::Duration d;
	  double x = static_cast<double>(absl::ToInt64Seconds(d));

	  // Suggested - Use the integer conversion function directly.
	  double x = absl::ToDoubleSeconds(d);

       Note: In	the second example, the	suggested fix could yield a  different
       result, as the conversion to integer could truncate.  In	practice, this
       is very rare, and you should use	absl::Trunc to perform this  operation
       explicitly instead.

   abseil-duration-division
       absl::Duration  arithmetic works	like it	does with integers. That means
       that division of	two absl::Duration objects returns an int64  with  any
       fractional  component truncated toward 0. See this link for more	infor-
       mation on arithmetic with absl::Duration.

       For example:

	  absl::Duration d = absl::Seconds(3.5);
	  int64	sec1 = d / absl::Seconds(1);	 // Truncates toward 0.
	  int64	sec2 = absl::ToInt64Seconds(d);	 // Equivalent to division.
	  assert(sec1 == 3 && sec2 == 3);

	  double dsec =	d / absl::Seconds(1);  // WRONG: Still truncates toward	0.
	  assert(dsec == 3.0);

       If  you	want  floating-point  division,	 you  should  use  either  the
       absl::FDivDuration()  function, or one of the unit conversion functions
       such as absl::ToDoubleSeconds().	For example:

	  absl::Duration d = absl::Seconds(3.5);
	  double dsec1 = absl::FDivDuration(d, absl::Seconds(1));  // GOOD: No truncation.
	  double dsec2 = absl::ToDoubleSeconds(d);		   // GOOD: No truncation.
	  assert(dsec1 == 3.5 && dsec2 == 3.5);

       This check looks	for uses of absl::Duration division that is done in  a
       floating-point  context,	 and recommends	the use	of a function that re-
       turns a floating-point value.

   abseil-duration-factory-float
       Checks  for  cases  where  the  floating-point  overloads  of   various
       absl::Duration factory functions	are called when	the more-efficient in-
       teger versions could be used instead.

       This check will not suggest fixes for literals which contain fractional
       floating	 point values or non-literals. It will suggest removing	super-
       fluous casts.

       Examples:

	  // Original -	Providing a floating-point literal.
	  absl::Duration d = absl::Seconds(10.0);

	  // Suggested - Use an	integer	instead.
	  absl::Duration d = absl::Seconds(10);

	  // Original -	Explicitly casting to a	floating-point type.
	  absl::Duration d = absl::Seconds(static_cast<double>(10));

	  // Suggested - Remove	the explicit cast
	  absl::Duration d = absl::Seconds(10);

   abseil-duration-factory-scale
       Checks for cases	where arguments	to  absl::Duration  factory  functions
       are scaled internally and could be changed to a different factory func-
       tion. This check	also looks for arguements with a zero value  and  sug-
       gests using absl::ZeroDuration()	instead.

       Examples:

	  // Original -	Internal multiplication.
	  int x;
	  absl::Duration d = absl::Seconds(60 *	x);

	  // Suggested - Use absl::Minutes instead.
	  absl::Duration d = absl::Minutes(x);

	  // Original -	Internal division.
	  int y;
	  absl::Duration d = absl::Milliseconds(y / 1000.);

	  // Suggested - Use absl:::Seconds instead.
	  absl::Duration d = absl::Seconds(y);

	  // Original -	Zero-value argument.
	  absl::Duration d = absl::Hours(0);

	  // Suggested = Use absl::ZeroDuration	instead
	  absl::Duration d = absl::ZeroDuration();

   abseil-duration-subtraction
       Checks for cases	where subtraction should be performed in the absl::Du-
       ration domain. When subtracting two values, and the first one is	 known
       to  be  a  conversion from absl::Duration, we can infer that the	second
       should also be interpreted as an	absl::Duration,	and make  that	infer-
       ence explicit.

       Examples:

	  // Original -	Subtraction in the double domain
	  double x;
	  absl::Duration d;
	  double result	= absl::ToDoubleSeconds(d) - x;

	  // Suggestion	- Subtraction in the absl::Duration domain instead
	  double result	= absl::ToDoubleSeconds(d - absl::Seconds(x));

	  // Original -	Subtraction of two Durations in	the double domain
	  absl::Duration d1, d2;
	  double result	= absl::ToDoubleSeconds(d1) - absl::ToDoubleSeconds(d2);

	  // Suggestion	- Subtraction in the absl::Duration domain instead
	  double result	= absl::ToDoubleSeconds(d1 - d2);

       Note:  As  with	other  clang-tidy checks, it is	possible that multiple
       fixes may overlap (as in	the case of nested expressions),  so  not  all
       occurences can be transformed in	one run. In particular,	this may occur
       for nested subtraction expressions. Running clang-tidy  multiple	 times
       will find and fix these overlaps.

   abseil-duration-unnecessary-conversion
       Finds  and  fixes cases where absl::Duration values are being converted
       to numeric types	and back again.

       Floating-point examples:

	  // Original -	Conversion to double and back again
	  absl::Duration d1;
	  absl::Duration d2 = absl::Seconds(absl::ToDoubleSeconds(d1));

	  // Suggestion	- Remove unnecessary conversions
	  absl::Duration d2 = d1;

	  // Original -	Division to convert to double and back again
	  absl::Duration d2 = absl::Seconds(absl::FDivDuration(d1, absl::Seconds(1)));

	  // Suggestion	- Remove division and conversion
	  absl::Duration d2 = d1;

       Integer examples:

	  // Original -	Conversion to integer and back again
	  absl::Duration d1;
	  absl::Duration d2 = absl::Hours(absl::ToInt64Hours(d1));

	  // Suggestion	- Remove unnecessary conversions
	  absl::Duration d2 = d1;

	  // Original -	Integer	division followed by conversion
	  absl::Duration d2 = absl::Seconds(d1 / absl::Seconds(1));

	  // Suggestion	- Remove division and conversion
	  absl::Duration d2 = d1;

       Note: Converting	to an integer and back to an absl::Duration might be a
       truncating  operation  if the value is not aligned to the scale of con-
       version.	 In the	rare case where	this is	the intended  result,  callers
       should use absl::Trunc to truncate explicitly.

   abseil-faster-strsplit-delimiter
       Finds  instances	of absl::StrSplit() or absl::MaxSplits() where the de-
       limiter is a single character string literal and	replaces with a	 char-
       acter.	The check will offer a suggestion to change the	string literal
       into a character.  It will also catch code using	absl::ByAnyChar()  for
       just a single character and will	transform that into a single character
       as well.

       These changes will give the same	result,	but  using  characters	rather
       than single character string literals is	more efficient and readable.

       Examples:

	  // Original -	the argument is	a string literal.
	  for (auto piece : absl::StrSplit(str,	"B")) {

	  // Suggested - the argument is a character, which causes the more efficient
	  // overload of absl::StrSplit() to be	used.
	  for (auto piece : absl::StrSplit(str,	'B')) {

	  // Original -	the argument is	a string literal inside	absl::ByAnyChar	call.
	  for (auto piece : absl::StrSplit(str,	absl::ByAnyChar("B"))) {

	  // Suggested - the argument is a character, which causes the more efficient
	  // overload of absl::StrSplit() to be	used and we do not need	absl::ByAnyChar
	  // anymore.
	  for (auto piece : absl::StrSplit(str,	'B')) {

	  // Original -	the argument is	a string literal inside	absl::MaxSplits	call.
	  for (auto piece : absl::StrSplit(str,	absl::MaxSplits("B", 1))) {

	  // Suggested - the argument is a character, which causes the more efficient
	  // overload of absl::StrSplit() to be	used.
	  for (auto piece : absl::StrSplit(str,	absl::MaxSplits('B', 1))) {
       subl.. title:: clang-tidy - abseil-no-internal-dependencies

   abseil-no-internal-dependencies
       Warns if	code using Abseil depends on internal details. If something is
       in a namespace that includes the	word ainternala, code is  not  allowed
       to  depend  upon	 it beaucse itas an implementation detail. They	cannot
       friend it, include it, you mention it or	refer to it in any way.	 Doing
       so  violates Abseil's compatibility guidelines and may result in	break-
       age. See	https://abseil.io/about/compatibility for more information.

       The following cases will	result in warnings:

	  absl::strings_internal::foo();
	  // warning triggered on this line
	  class	foo {
	    friend struct absl::container_internal::faa;
	    // warning triggered on this line
	  };
	  absl::memory_internal::MakeUniqueResult();
	  // warning triggered on this line

   abseil-no-namespace
       Ensures code does not open namespace absl  as  that  violates  Abseil's
       compatibility  guidelines.  Code	should not open	namespace absl as that
       conflicts with Abseil's compatibility  guidelines  and  may  result  in
       breakage.

       Any code	that uses:

	  namespace absl {
	   ...
	  }

       will be prompted	with a warning.

       See the full Abseil compatibility guidelines for	more information.

   abseil-redundant-strcat-calls
       Suggests	 removal  of unnecessary calls to absl::StrCat when the	result
       is being	passed to another call to absl::StrCat or absl::StrAppend.

       The extra calls cause unnecessary temporary strings to be  constructed.
       Removing	them makes the code smaller and	faster.

       Examples:

	  std::string s	= absl::StrCat("A", absl::StrCat("B", absl::StrCat("C",	"D")));
	  //before

	  std::string s	= absl::StrCat("A", "B", "C", "D");
	  //after

	  absl::StrAppend(&s, absl::StrCat("E",	"F", "G"));
	  //before

	  absl::StrAppend(&s, "E", "F",	"G");
	  //after

   abseil-str-cat-append
       Flags  uses  of	absl::StrCat()	to  append  to a std::string. Suggests
       absl::StrAppend() should	be used	instead.

       The extra calls cause unnecessary temporary strings to be  constructed.
       Removing	them makes the code smaller and	faster.

	  a = absl::StrCat(a, b); // Use absl::StrAppend(&a, b)	instead.

       Does  not diagnose cases	where absl::StrCat() is	used as	a template ar-
       gument for a functor.

   abseil-string-find-startswith
       Checks whether a	std::string::find() result is  compared	 with  0,  and
       suggests	 replacing with	absl::StartsWith(). This is both a readability
       and performance issue.

	  string s = "...";
	  if (s.find("Hello World") == 0) { /* do something */ }

       becomes

	  string s = "...";
	  if (absl::StartsWith(s, "Hello World")) { /* do something */ }

   Options
       StringLikeClasses
	      Semicolon-separated list of names	of string-like classes.	By de-
	      fault  only std::basic_string is considered. The list of methods
	      to considered is fixed.

       IncludeStyle
	      A	string specifying which	include-style is used, llvm or google.
	      Default is llvm.

       AbseilStringsMatchHeader
	      The   location   of   Abseil's   strings/match.h.	  Defaults  to
	      absl/strings/match.h.

   abseil-time-comparison
       Prefer comparisons in the absl::Time domain instead of the integer  do-
       main.

       N.B.:  In  cases	 where an absl::Time is	being converted	to an integer,
       alignment may occur. If the comparison depends on this alignment, doing
       the  comparison	in the absl::Time domain may yield a different result.
       In practice this	is very	rare, and still	indicates a bug	 which	should
       be fixed.

       Examples:

	  // Original -	Comparison in the integer domain
	  int x;
	  absl::Time t;
	  if (x	< absl::ToUnixSeconds(t)) ...

	  // Suggested - Compare in the	absl::Time domain instead
	  if (absl::FromUnixSeconds(x) < t) ...

   abseil-time-subtraction
       Finds and fixes absl::Time subtraction expressions to do	subtraction in
       the Time	domain instead of the numeric domain.

       There are two cases of Time subtraction in which	deduce additional type
       information:

       o When  the  result  is	an absl::Duration and the first	argument is an
	 absl::Time.

       o When the second argument is a absl::Time.

       In the first case, we must know the  result  of	the  operation,	 since
       without	that  the  second  operand could be either an absl::Time or an
       absl::Duration.	In the second case,  the  first	 operand  must	be  an
       absl::Time, because subtracting an absl::Time from an absl::Duration is
       not defined.

       Examples:

	  int x;
	  absl::Time t;

	  // Original -	absl::Duration result and first	operand	is a absl::Time.
	  absl::Duration d = absl::Seconds(absl::ToUnixSeconds(t) - x);

	  // Suggestion	- Perform subtraction in the Time domain instead.
	  absl::Duration d = t - absl::FromUnixSeconds(x);

	  // Original -	Second operand is an absl::Time.
	  int i	= x - absl::ToUnixSeconds(t);

	  // Suggestion	- Perform subtraction in the Time domain instead.
	  int i	= absl::ToInt64Seconds(absl::FromUnixSeconds(x)	- t);

   abseil-upgrade-duration-conversions
       Finds calls to absl::Duration arithmetic	operators and factories	 whose
       argument	 needs	an  explicit cast to continue compiling	after upcoming
       API changes.

       The operators *=, /=, *,	and / for absl::Duration currently  accept  an
       argument	 of class type that is convertible to an arithmetic type. Such
       a call currently	converts the value to an int64_t, even in a case  such
       as std::atomic<float> that would	result in lossy	conversion.

       Additionally,   the   absl::Duration  factory  functions	 (absl::Hours,
       absl::Minutes, etc) currently accept an	int64_t	 or  a	floating-point
       type.  Similar  to  the arithmetic operators, calls with	an argument of
       class type that is convertible to an arithmetic	type  go  through  the
       int64_t path.

       These operators and factories will be changed to	only accept arithmetic
       types to	prevent	unintended behavior. After these changes are released,
       passing	an  argument of	class type will	no longer compile, even	if the
       type is implicitly convertible to an arithmetic type.

       Here are	example	fixes created by this check:

	  std::atomic<int> a;
	  absl::Duration d = absl::Milliseconds(a);
	  d *= a;

       becomes

	  std::atomic<int> a;
	  absl::Duration d = absl::Milliseconds(static_cast<int64_t>(a));
	  d *= static_cast<int64_t>(a);

       Note that this check always adds	a cast to int64_t in order to preserve
       the  current  behavior  of user code. It	is possible that this uncovers
       unintended behavior due to types	implicitly  convertible	 to  a	float-
       ing-point type.

   android-cloexec-accept
       The usage of accept() is	not recommended, it's better to	use accept4().
       Without this flag, an opened sensitive  file  descriptor	 would	remain
       open across a fork+exec to a lower-privileged SELinux domain.

       Examples:

	  accept(sockfd, addr, addrlen);

	  // becomes

	  accept4(sockfd, addr,	addrlen, SOCK_CLOEXEC);

   android-cloexec-accept4
       accept4() should	include	SOCK_CLOEXEC in	its type argument to avoid the
       file descriptor leakage.	Without	this flag, an  opened  sensitive  file
       would  remain open across a fork+exec to	a lower-privileged SELinux do-
       main.

       Examples:

	  accept4(sockfd, addr,	addrlen, SOCK_NONBLOCK);

	  // becomes

	  accept4(sockfd, addr,	addrlen, SOCK_NONBLOCK | SOCK_CLOEXEC);

   android-cloexec-creat
       The usage of creat() is not recommended,	it's better to use open().

       Examples:

	  int fd = creat(path, mode);

	  // becomes

	  int fd = open(path, O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC,	mode);

   android-cloexec-dup
       The usage of dup() is not recommended,  it's  better  to	 use  fcntl(),
       which  can  set	the close-on-exec flag.	Otherwise, an opened sensitive
       file would remain open across a fork+exec to a lower-privileged SELinux
       domain.

       Examples:

	  int fd = dup(oldfd);

	  // becomes

	  int fd = fcntl(oldfd,	F_DUPFD_CLOEXEC);

   android-cloexec-epoll-create
       The  usage  of  epoll_create()  is  not recommended, it's better	to use
       epoll_create1(),	which allows close-on-exec.

       Examples:

	  epoll_create(size);

	  // becomes

	  epoll_create1(EPOLL_CLOEXEC);

   android-cloexec-epoll-create1
       epoll_create1() should include EPOLL_CLOEXEC in its  type  argument  to
       avoid  the file descriptor leakage. Without this	flag, an opened	sensi-
       tive file would remain open across a fork+exec  to  a  lower-privileged
       SELinux domain.

       Examples:

	  epoll_create1(0);

	  // becomes

	  epoll_create1(EPOLL_CLOEXEC);

   android-cloexec-fopen
       fopen()	should	include	 e in their mode string; so re would be	valid.
       This is equivalent to having set	FD_CLOEXEC on that descriptor.

       Examples:

	  fopen("fn", "r");

	  // becomes

	  fopen("fn", "re");

   android-cloexec-inotify-init
       The usage of inotify_init() is not recommended, it's better to use ino-
       tify_init1().

       Examples:

	  inotify_init();

	  // becomes

	  inotify_init1(IN_CLOEXEC);

   android-cloexec-inotify-init1
       inotify_init1() should include IN_CLOEXEC in its	type argument to avoid
       the file	descriptor leakage. Without this  flag,	 an  opened  sensitive
       file would remain open across a fork+exec to a lower-privileged SELinux
       domain.

       Examples:

	  inotify_init1(IN_NONBLOCK);

	  // becomes

	  inotify_init1(IN_NONBLOCK | IN_CLOEXEC);

   android-cloexec-memfd-create
       memfd_create() should include MFD_CLOEXEC in its	type argument to avoid
       the  file  descriptor  leakage.	Without	this flag, an opened sensitive
       file would remain open across a fork+exec to a lower-privileged SELinux
       domain.

       Examples:

	  memfd_create(name, MFD_ALLOW_SEALING);

	  // becomes

	  memfd_create(name, MFD_ALLOW_SEALING | MFD_CLOEXEC);

   android-cloexec-open
       A  common source	of security bugs is code that opens a file without us-
       ing the O_CLOEXEC flag.	Without	that flag, an  opened  sensitive  file
       would  remain open across a fork+exec to	a lower-privileged SELinux do-
       main,  leaking  that  sensitive	data.  Open-like  functions  including
       open(),	openat(), and open64() should include O_CLOEXEC	in their flags
       argument.

       Examples:

	  open("filename", O_RDWR);
	  open64("filename", O_RDWR);
	  openat(0, "filename",	O_RDWR);

	  // becomes

	  open("filename", O_RDWR | O_CLOEXEC);
	  open64("filename", O_RDWR | O_CLOEXEC);
	  openat(0, "filename",	O_RDWR | O_CLOEXEC);

   android-cloexec-pipe
       This check detects usage	of pipe(). Using pipe()	 is  not  recommended,
       pipe2() is the suggested	replacement. The check also adds the O_CLOEXEC
       flag that marks the file	descriptor to be closed	 in  child  processes.
       Without	this flag a sensitive file descriptor can be leaked to a child
       process,	potentially into a lower-privileged SELinux domain.

       Examples:

	  pipe(pipefd);

       Suggested replacement:

	  pipe2(pipefd,	O_CLOEXEC);

   android-cloexec-pipe2
       This checks ensures that	pipe2()	is called with the O_CLOEXEC flag. The
       check also adds the O_CLOEXEC flag that marks the file descriptor to be
       closed in child processes.  Without this	flag a sensitive file descrip-
       tor  can	 be leaked to a	child process, potentially into	a lower-privi-
       leged SELinux domain.

       Examples:

	  pipe2(pipefd,	O_NONBLOCK);

       Suggested replacement:

	  pipe2(pipefd,	O_NONBLOCK | O_CLOEXEC);

   android-cloexec-socket
       socket()	should include SOCK_CLOEXEC in its type	argument to avoid  the
       file  descriptor	 leakage.  Without this	flag, an opened	sensitive file
       would remain open across	a fork+exec to a lower-privileged SELinux  do-
       main.

       Examples:

	  socket(domain, type, SOCK_STREAM);

	  // becomes

	  socket(domain, type, SOCK_STREAM | SOCK_CLOEXEC);

   android-comparison-in-temp-failure-retry
       Diagnoses comparisons that appear to be incorrectly placed in the argu-
       ment to the TEMP_FAILURE_RETRY macro. Having such a use is incorrect in
       the  vast majority of cases, and	will often silently defeat the purpose
       of the TEMP_FAILURE_RETRY macro.

       For context, TEMP_FAILURE_RETRY is a convenience	macro provided by both
       glibc  and  Bionic. Its purpose is to repeatedly	run a syscall until it
       either succeeds,	or fails for reasons other than	being interrupted.

       Example buggy usage looks like:

	  char cs[1];
	  while	(TEMP_FAILURE_RETRY(read(STDIN_FILENO, cs, sizeof(cs)) != 0)) {
	    // Do something with cs.
	  }

       Because TEMP_FAILURE_RETRY will check for whether  the  result  of  the
       comparison is -1, and retry if so.

       If  you	encounter  this, the fix is simple: lift the comparison	out of
       the TEMP_FAILURE_RETRY argument,	like so:

	  char cs[1];
	  while	(TEMP_FAILURE_RETRY(read(STDIN_FILENO, cs, sizeof(cs)))	!= 0) {
	    // Do something with cs.
	  }

   boost-use-to-string
       This check finds	conversion from	integer	type like int  to  std::string
       or std::wstring using boost::lexical_cast, and replace it with calls to
       std::to_string and std::to_wstring.

       It  doesn't  replace  conversion	 from  floating	 points	 despite   the
       to_string overloads, because it would change the	behaviour.

	  auto str = boost::lexical_cast<std::string>(42);
	  auto wstr = boost::lexical_cast<std::wstring>(2137LL);

	  // Will be changed to
	  auto str = std::to_string(42);
	  auto wstr = std::to_wstring(2137LL);

   bugprone-argument-comment
       Checks that argument comments match parameter names.

       The check understands argument comments in the form /*parameter_name=*/
       that are	placed right before the	argument.

	  void f(bool foo);

	  ...

	  f(/*bar=*/true);
	  // warning: argument name 'bar' in comment does not match parameter name 'foo'

       The check tries to detect typos and suggest automated fixes for them.

   Options
       StrictMode
	      When zero	(default value), the check  will  ignore  leading  and
	      trailing	underscores and	case when comparing names -- otherwise
	      they are taken into account.

       CommentBoolLiterals
	      When true, the check will	add argument comments  in  the	format
	      /*ParameterName=*/ right before the boolean literal argument.

       Before:

	  void foo(bool	TurnKey, bool PressButton);

	  foo(true, false);

       After:

	  void foo(bool	TurnKey, bool PressButton);

	  foo(/*TurnKey=*/true,	/*PressButton=*/false);

       CommentIntegerLiterals
	      When  true,  the	check will add argument	comments in the	format
	      /*ParameterName=*/ right before the integer literal argument.

       Before:

	  void foo(int MeaningOfLife);

	  foo(42);

       After:

	  void foo(int MeaningOfLife);

	  foo(/*MeaningOfLife=*/42);

       CommentFloatLiterals
	      When true, the check will	add argument comments  in  the	format
	      /*ParameterName=*/  right	 before	the float/double literal argu-
	      ment.

       Before:

	  void foo(float Pi);

	  foo(3.14159);

       After:

	  void foo(float Pi);

	  foo(/*Pi=*/3.14159);

       CommentStringLiterals
	      When true, the check will	add argument comments  in  the	format
	      /*ParameterName=*/ right before the string literal argument.

       Before:

	  void foo(const char *String);
	  void foo(const wchar_t *WideString);

	  foo("Hello World");
	  foo(L"Hello World");

       After:

	  void foo(const char *String);
	  void foo(const wchar_t *WideString);

	  foo(/*String=*/"Hello	World");
	  foo(/*WideString=*/L"Hello World");

       CommentCharacterLiterals
	      When  true,  the	check will add argument	comments in the	format
	      /*ParameterName=*/ right before the character literal argument.

       Before:

	  void foo(char	*Character);

	  foo('A');

       After:

	  void foo(char	*Character);

	  foo(/*Character=*/'A');

       CommentUserDefinedLiterals
	      When true, the check will	add argument comments  in  the	format
	      /*ParameterName=*/  right	 before	the user defined literal argu-
	      ment.

       Before:

	  void foo(double Distance);

	  double operator"" _km(long double);

	  foo(402.0_km);

       After:

	  void foo(double Distance);

	  double operator"" _km(long double);

	  foo(/*Distance=*/402.0_km);

       CommentNullPtrs
	      When true, the check will	add argument comments  in  the	format
	      /*ParameterName=*/ right before the nullptr literal argument.

       Before:

	  void foo(A* Value);

	  foo(nullptr);

       After:

	  void foo(A* Value);

	  foo(/*Value=*/nullptr);

   bugprone-assert-side-effect
       Finds assert() with side	effect.

       The condition of	assert() is evaluated only in debug builds so a	condi-
       tion with side effect can cause different behavior in debug  /  release
       builds.

   Options
       AssertMacros
	      A	 comma-separated  list	of  the	 names	of assert macros to be
	      checked.

       CheckFunctionCalls
	      Whether to treat non-const member	and  non-member	 functions  as
	      they  produce  side  effects. Disabled by	default	because	it can
	      increase the number of false positive warnings.

   bugprone-bool-pointer-implicit-conversion
       Checks for conditions based on implicit conversion from a bool  pointer
       to bool.

       Example:

	  bool *p;
	  if (p) {
	    // Never used in a pointer-specific	way.
	  }

   bugprone-branch-clone
       Checks for repeated branches in if/else if/else chains, consecutive re-
       peated branches in switch statements  and  indentical  true  and	 false
       branches	in conditional operators.

	  if (test_value(x)) {
	    y++;
	    do_something(x, y);
	  } else {
	    y++;
	    do_something(x, y);
	  }

       In  this	 simple	example	(which could arise e.g.	as a copy-paste	error)
       the then	and else branches are identical	and the	code is	equivalent the
       following shorter and cleaner code:

	  test_value(x); // can	be omitted unless it has side effects
	  y++;
	  do_something(x, y);

       If  this	is the inteded behavior, then there is no reason to use	a con-
       ditional	statement; otherwise the issue can be  solved  by  fixing  the
       branch that is handled incorrectly.

       The  check  also	 detects  repeated  branches in	longer if/else if/else
       chains where it would be	even harder to notice the problem.

       In switch statements the	check only reports repeated branches when they
       are  consecutive, because it is relatively common that the case:	labels
       have some natural ordering and  rearranging  them  would	 decrease  the
       readability of the code.	For example:

	  switch (ch) {
	  case 'a':
	    return 10;
	  case 'A':
	    return 10;
	  case 'b':
	    return 11;
	  case 'B':
	    return 11;
	  default:
	    return 10;
	  }

       Here the	check reports that the 'a' and 'A' branches are	identical (and
       that the	'b' and	'B' branches are also identical), but does not	report
       that  the  default:  branch is also idenical to the first two branches.
       If this is indeed the correct behavior, then it	could  be  implemented
       as:

	  switch (ch) {
	  case 'a':
	  case 'A':
	    return 10;
	  case 'b':
	  case 'B':
	    return 11;
	  default:
	    return 10;
	  }

       Here the	check does not warn for	the repeated return 10;, which is good
       if we want to preserve that 'a' is before 'b' and default: is the  last
       branch.

       Finally,	the check also examines	conditional operators and reports code
       like:

	  return test_value(x) ? x : x;

       Unlike if statements, the check does not	detect chains  of  conditional
       operators.

       Note:  This check also reports situations where branches	become identi-
       cal only	after preprocession.

   bugprone-copy-constructor-init
       Finds copy constructors where the constructor  doesn't  call  the  copy
       constructor of the base class.

	  class	Copyable {
	  public:
	    Copyable() = default;
	    Copyable(const Copyable &) = default;
	  };
	  class	X2 : public Copyable {
	    X2(const X2	&other)	{} // Copyable(other) is missing
	  };

       Also  finds  copy  constructors where the constructor of	the base class
       don't have parameter.

	  class	X4 : public Copyable {
	    X4(const X4	&other)	: Copyable() {}	// other is missing
	  };

       The check also suggests a fix-its in some cases.

   bugprone-dangling-handle
       Detect  dangling	 references  in	 value	handles	 like  std::experimen-
       tal::string_view.   These  dangling  references can be a	result of con-
       structing handles from temporary	values,	where  the  temporary  is  de-
       stroyed soon after the handle is	created.

       Examples:

	  string_view View = string();	// View	will dangle.
	  string A;
	  View = A + "A";  // still dangle.

	  vector<string_view> V;
	  V.push_back(string());  // V[0] is dangling.
	  V.resize(3, string());  // V[1] and V[2] will	also dangle.

	  string_view f() {
	    // All these return	values will dangle.
	    return string();
	    string S;
	    return S;
	    char Array[10]{};
	    return Array;
	  }

   Options
       HandleClasses
	      A	semicolon-separated list of class names	that should be treated
	      as   handles.    By    default	only	std::experimental::ba-
	      sic_string_view is considered.

   bugprone-exception-escape
       Finds  functions	 which	may throw an exception directly	or indirectly,
       but they	should not. The	functions which	should	not  throw  exceptions
       are  the	following: * Destructors * Move	constructors * Move assignment
       operators * The main() functions	* swap() functions * Functions	marked
       with throw() or noexcept	* Other	functions given	as option

       A  destructor  throwing	an exception may result	in undefined behavior,
       resource	leaks or unexpected termination	of the program.	Throwing  move
       constructor or move assignment also may result in undefined behavior or
       resource	leak. The swap() operations expected to	be non	throwing  most
       of  the cases and they are always possible to implement in a non	throw-
       ing way.	Non throwing swap() operations are also	used  to  create  move
       operations.  A throwing main() function also results in unexpected ter-
       mination.

       WARNING!	This check may be expensive on large source files.

   Options
       FunctionsThatShouldNotThrow
	      Comma separated list containing function names which should  not
	      throw.  An example value for this	parameter can be WinMain which
	      adds function WinMain() in the Windows API to the	 list  of  the
	      funcions	which  should  not  throw.  Default  value is an empty
	      string.

       IgnoredExceptions
	      Comma separated list containing type names which are not counted
	      as  thrown  exceptions  in  the check. Default value is an empty
	      string.

   bugprone-fold-init-type
       The check flags type mismatches	in  folds  like	 std::accumulate  that
       might  result  in  loss	of  precision.	std::accumulate	folds an input
       range into an initial value using the type of the latter,  with	opera-
       tor+ by default.	This can cause loss of precision through:

       o Truncation: The following code	uses a floating	point range and	an int
	 initial value,	so trucation wil happen	at every application of	opera-
	 tor+  and  the	result will be 0, which	might not be what the user ex-
	 pected.

	  auto a = {0.5f, 0.5f,	0.5f, 0.5f};
	  return std::accumulate(std::begin(a),	std::end(a), 0);

       o Overflow: The following code also returns 0.

	  auto a = {65536LL * 65536 * 65536};
	  return std::accumulate(std::begin(a),	std::end(a), 0);

   bugprone-forward-declaration-namespace
       Checks if an unused forward declaration is in a wrong namespace.

       The check inspects all unused forward declarations and checks if	 there
       is  any declaration/definition with the same name existing, which could
       indicate	that the forward declaration is	in a potentially  wrong	 name-
       space.

	  namespace na { struct	A; }
	  namespace nb { struct	A {}; }
	  nb::A	a;
	  // warning : no definition found for 'A', but	a definition with the same name
	  // 'A' found in another namespace 'nb::'

       This  check  can	 only generate warnings, but it	can't suggest a	fix at
       this point.

   bugprone-forwarding-reference-overload
       The check looks for perfect forwarding constructors that	can hide  copy
       or  move	constructors. If a non const lvalue reference is passed	to the
       constructor, the	forwarding reference parameter will be a better	 match
       than the	const reference	parameter of the copy constructor, so the per-
       fect forwarding constructor will	be called,  which  can	be  confusing.
       For  detailed  description  of  this issue see: Scott Meyers, Effective
       Modern C++, Item	26.

       Consider	the following example:

	  class	Person {
	  public:
	    // C1: perfect forwarding ctor
	    template<typename T>
	    explicit Person(T&&	n) {}

	    // C2: perfect forwarding ctor with	parameter default value
	    template<typename T>
	    explicit Person(T&&	n, int x = 1) {}

	    // C3: perfect forwarding ctor guarded with	enable_if
	    template<typename T, typename X = enable_if_t<is_special<T>,void>>
	    explicit Person(T&&	n) {}

	    // (possibly compiler generated) copy ctor
	    Person(const Person& rhs);
	  };

       The check warns for constructors	C1 and C2, because those can hide copy
       and  move  constructors.	 We suppress warnings if the copy and the move
       constructors are	both disabled (deleted or private), because  there  is
       nothing	the perfect forwarding constructor could hide in this case. We
       also suppress warnings for constructors like C3 that are	 guarded  with
       an enable_if, assuming the programmer was aware of the possible hiding.

   Background
       For  deciding  whether a	constructor is guarded with enable_if, we con-
       sider the default values	of the type parameters and the	types  of  the
       constructor parameters. If any part of these types is std::enable_if or
       std::enable_if_t, we assume the constructor is guarded.

   bugprone-inaccurate-erase
       Checks for inaccurate use of the	erase()	method.

       Algorithms like remove()	do not actually	remove any  element  from  the
       container  but return an	iterator to the	first redundant	element	at the
       end of the container. These redundant elements must  be	removed	 using
       the  erase() method. This check warns when not all of the elements will
       be removed due to using an inappropriate	overload.

       For example, the	following code erases only one element:

	  std::vector<int> xs;
	  ...
	  xs.erase(std::remove(xs.begin(), xs.end(), 10));

       Call the	two-argument overload of erase() to remove the subrange:

	  std::vector<int> xs;
	  ...
	  xs.erase(std::remove(xs.begin(), xs.end(), 10), xs.end());

   bugprone-incorrect-roundings
       Checks the usage	of patterns known to produce incorrect rounding.  Pro-
       grammers	often use:

	  (int)(double_expression + 0.5)

       to round	the double expression to an integer. The problem with this:

       1. It is	unnecessarily slow.

       2. It  is  incorrect.  The  number  0.499999975 (smallest representable
	  float	number below 0.5) rounds to 1.0. Even worse behavior for nega-
	  tive numbers where both -0.5f	and -1.4f both round to	0.0.

   bugprone-integer-division
       Finds  cases  where  integer  division  in  a floating point context is
       likely to cause unintended loss of precision.

       No reports are made if divisions	are part of the	following expressions:

       o operands of operators expecting integral or bool types,

       o call expressions of integral or bool types, and

       o explicit cast expressions to integral or bool types,

       as these	are interpreted	as signs of deliberateness from	 the  program-
       mer.

       Examples:

	  float	floatFunc(float);
	  int intFunc(int);
	  double d;
	  int i	= 42;

	  // Warn, floating-point values expected.
	  d = 32 * 8 / (2 + i);
	  d = 8	* floatFunc(1 +	7 / 2);
	  d = i	/ (1 <<	4);

	  // OK, no integer division.
	  d = 32 * 8.0 / (2 + i);
	  d = 8	* floatFunc(1 +	7.0 / 2);
	  d = (double)i	/ (1 <<	4);

	  // OK, there are signs of deliberateness.
	  d = 1	<< (i /	2);
	  d = 9	+ intFunc(6 * i	/ 32);
	  d = (int)(i /	32) - 8;

   bugprone-lambda-function-name
       Checks  for attempts to get the name of a function from within a	lambda
       expression. The name of a lambda	is always something  like  operator(),
       which is	almost never what was intended.

       Example:

	  void FancyFunction() {
	    [] { printf("Called	from %s\n", __func__); }();
	    [] { printf("Now called from %s\n",	__FUNCTION__); }();
	  }

       Output:

	  Called from operator()
	  Now called from operator()

       Likely intended output:

	  Called from FancyFunction
	  Now called from FancyFunction

   bugprone-macro-parentheses
       Finds  macros  that can have unexpected behaviour due to	missing	paren-
       theses.

       Macros are expanded by the preprocessor as-is. As a result,  there  can
       be unexpected behaviour;	operators may be evaluated in unexpected order
       and unary operators may become binary operators,	etc.

       When the	replacement list has an	expression, it is recommended to  sur-
       round it	with parentheses. This ensures that the	macro result is	evalu-
       ated completely before it is used.

       It is also recommended to surround macro	arguments in  the  replacement
       list  with  parentheses.	This ensures that the argument value is	calcu-
       lated properly.

   bugprone-macro-repeated-side-effects
       Checks for repeated argument with side effects in macros.

   bugprone-misplaced-operator-in-strlen-in-alloc
       Finds cases where 1 is added to the string in the argument to strlen(),
       strnlen(), strnlen_s(), wcslen(), wcsnlen(), and	wcsnlen_s() instead of
       the result and the value	is used	as an argument to a memory  allocation
       function	 (malloc(), calloc(), realloc(), alloca()) or the new[]	opera-
       tor in C++. The check detects error cases even if one  of  these	 func-
       tions  (except  the  new[]  operator)  is called	by a constant function
       pointer.	 Cases where 1 is added	both to	the parameter and  the	result
       of the strlen()-like function are ignored, as are cases where the whole
       addition	is surrounded by extra parentheses.

       C example code:

	  void bad_malloc(char *str) {
	    char *c = (char*) malloc(strlen(str	+ 1));
	  }

       The suggested fix is to add 1 to	the return value of strlen()  and  not
       to its argument.	In the example above the fix would be

	  char *c = (char*) malloc(strlen(str) + 1);

       C++ example code:

	  void bad_new(char *str) {
	    char *c = new char[strlen(str + 1)];
	  }

       As  in  the  C code with	the malloc() function, the suggested fix is to
       add 1 to	the return value of strlen() and not to	its argument.  In  the
       example above the fix would be

	  char *c = new	char[strlen(str) + 1];

       Example for silencing the diagnostic:

	  void bad_malloc(char *str) {
	    char *c = (char*) malloc(strlen((str + 1)));
	  }

   bugprone-misplaced-widening-cast
       This  check will	warn when there	is a cast of a calculation result to a
       bigger type. If the intention of	the cast is to avoid loss of precision
       then  the cast is misplaced, and	there can be loss of precision.	Other-
       wise the	cast is	ineffective.

       Example code:

	  long f(int x)	{
	      return (long)(x *	1000);
	  }

       The result x * 1000 is first calculated using int precision. If the re-
       sult  exceeds int precision there is loss of precision. Then the	result
       is casted to long.

       If there	is no loss of precision	then the cast can be  removed  or  you
       can explicitly cast to int instead.

       If  you	want  to avoid loss of precision then put the cast in a	proper
       location, for instance:

	  long f(int x)	{
	      return (long)x * 1000;
	  }

   Implicit casts
       Forgetting to place the cast at all is at least	as  dangerous  and  at
       least  as common	as misplacing it. If CheckImplicitCasts	is enabled the
       check also detects these	cases, for instance:

	  long f(int x)	{
	      return x * 1000;
	  }

   Floating point
       Currently warnings are only written for integer conversion. No  warning
       is written for this code:

	  double f(float x) {
	      return (double)(x	* 10.0f);
	  }

   Options
       CheckImplicitCasts
	      If  non-zero,  enables  detection	 of implicit casts. Default is
	      non-zero.

   bugprone-move-forwarding-reference
       Warns if	std::move is called on a forwarding reference, for example:

	  template <typename T>
	  void foo(T&& t) {
	    bar(std::move(t));
	  }

       Forwarding references should typically be passed	 to  std::forward  in-
       stead of	std::move, and this is the fix that will be suggested.

       (A  forwarding reference	is an rvalue reference of a type that is a de-
       duced function template argument.)

       In this example,	the suggested fix would	be

	  bar(std::forward<T>(t));

   Background
       Code like the example above is sometimes	written	with  the  expectation
       that  T&&  will always end up being an rvalue reference,	no matter what
       type is deduced for T, and that it is therefore not possible to pass an
       lvalue to foo().	However, this is not true. Consider this example:

	  std::string s	= "Hello, world";
	  foo(s);

       This  code compiles and,	after the call to foo(), s is left in an inde-
       terminate state because it has been moved from. This may	be  surprising
       to  the	caller	of  foo()  because  no std::move was used when calling
       foo().

       The reason for this behavior lies in the	special	rule for template  ar-
       gument  deduction  on function templates	like foo() -- i.e. on function
       templates that take an rvalue reference argument	of a type  that	 is  a
       deduced	function  template argument. (See section [temp.deduct.call]/3
       in the C++11 standard.)

       If foo()	is called on an	lvalue (as in the example above),  then	 T  is
       deduced	to  be an lvalue reference. In the example, T is deduced to be
       std::string  &.	The  type  of  the  argument   t   therefore   becomes
       std::string&  &&;  by the reference collapsing rules, this collapses to
       std::string&.

       This means that the foo(s) call passes s	as an  lvalue  reference,  and
       foo()  ends  up	moving	s and thereby placing it into an indeterminate
       state.

   bugprone-multiple-statement-macro
       Detect multiple statement macros	that are used in  unbraced  condition-
       als.  Only  the	first statement	of the macro will be inside the	condi-
       tional and the other ones will be executed unconditionally.

       Example:

	  #define INCREMENT_TWO(x, y) (x)++; (y)++
	  if (do_increment)
	    INCREMENT_TWO(a, b);  // (b)++ will	be executed unconditionally.

   bugprone-parent-virtual-call
       Detects and fixes calls to grand-...parent virtual methods  instead  of
       calls to	overridden parent's virtual methods.

	  struct A {
	    int	virtual	foo() {...}
	  };

	  struct B: public A {
	    int	foo() override {...}
	  };

	  struct C: public B {
	    int	foo() override { A::foo(); }
	  //			 ^^^^^^^^
	  // warning: qualified	name A::foo refers to a	member overridden in subclass; did you mean 'B'?  [bugprone-parent-virtual-call]
	  };

   bugprone-posix-return
       Checks  if  any	calls  to POSIX	functions (except posix_openpt)	expect
       negative	return values. These functions return either 0 on  success  or
       an errno	on failure, which is positive only.

       Example buggy usage looks like:

	  if (posix_fadvise(...) < 0) {

       This  will  never  happen as the	return value is	always non-negative. A
       simple fix could	be:

	  if (posix_fadvise(...) > 0) {

   bugprone-sizeof-container
       The check finds usages of sizeof	on expressions of STL container	types.
       Most likely the user wanted to use .size() instead.

       All  class/struct  types	 declared  in  namespace  std::	having a const
       size()  method  are  considered	containers,  with  the	exception   of
       std::bitset and std::array.

       Examples:

	  std::string s;
	  int a	= 47 + sizeof(s); // warning: sizeof() doesn't return the size of the container. Did you mean .size()?

	  int b	= sizeof(std::string); // no warning, probably intended.

	  std::string array_of_strings[10];
	  int c	= sizeof(array_of_strings) / sizeof(array_of_strings[0]); // no	warning, definitely intended.

	  std::array<int, 3> std_array;
	  int d	= sizeof(std_array); //	no warning, probably intended.

   bugprone-sizeof-expression
       The  check finds	usages of sizeof expressions which are most likely er-
       rors.

       The sizeof operator yields the size (in bytes) of  its  operand,	 which
       may  be	an  expression	or the parenthesized name of a type. Misuse of
       this operator may be leading to errors and possible  software  vulnera-
       bilities.

   Suspicious usage of 'sizeof(K)'
       A  common mistake is to query the sizeof	of an integer literal. This is
       equivalent to query the size of its type	(probably int).	The intent  of
       the programmer was probably to simply get the integer and not its size.

	  #define BUFLEN 42
	  char buf[BUFLEN];
	  memset(buf, 0, sizeof(BUFLEN));  // sizeof(42) ==> sizeof(int)

   Suspicious usage of 'sizeof(expr)'
       In cases, where there is	an enum	or integer to represent	a type,	a com-
       mon mistake is to query the sizeof on the integer or enum  that	repre-
       sents  the type that should be used by sizeof. This results in the size
       of the integer and not of the type the integer represents:

	  enum data_type {
	    FLOAT_TYPE,
	    DOUBLE_TYPE
	  };

	  struct data {
	    data_type type;
	    void* buffer;
	    data_type get_type() {
	      return type;
	    }
	  };

	  void f(data d, int numElements) {
	    // should be sizeof(float) or sizeof(double), depending on d.get_type()
	    int	numBytes = numElements * sizeof(d.get_type());
	    ...
	  }

   Suspicious usage of 'sizeof(this)'
       The this	keyword	is evaluated to	a pointer to  an  object  of  a	 given
       type.   The expression sizeof(this) is returning	the size of a pointer.
       The programmer most likely wanted the size of the object	 and  not  the
       size of the pointer.

	  class	Point {
	    [...]
	    size_t size() { return sizeof(this); }  // should probably be sizeof(*this)
	    [...]
	  };

   Suspicious usage of 'sizeof(char*)'
       There  is  a  subtle difference between declaring a string literal with
       char* A = "" and	char A[] = "". The first case has the type  char*  in-
       stead  of the aggregate type char[]. Using sizeof on an object declared
       with char* type is returning the	size of	a pointer instead of the  num-
       ber of characters (bytes) in the	string literal.

	  const	char* kMessage = "Hello	World!";      // const char kMessage[] = "...";
	  void getMessage(char*	buf) {
	    memcpy(buf,	kMessage, sizeof(kMessage));  // sizeof(char*)
	  }

   Suspicious usage of 'sizeof(A*)'
       A  common  mistake  is  to compute the size of a	pointer	instead	of its
       pointee.	 These cases may occur because of explicit  cast  or  implicit
       conversion.

	  int A[10];
	  memset(A, 0, sizeof(A	+ 0));

	  struct Point point;
	  memset(point,	0, sizeof(&point));

   Suspicious usage of 'sizeof(...)/sizeof(...)'
       Dividing	sizeof expressions is typically	used to	retrieve the number of
       elements	of an aggregate. This check warns on  incompatible  or	suspi-
       cious cases.

       In  the	following example, the entity has 10-bytes and is incompatible
       with the	type int which has 4 bytes.

	  char buf[] = { 0, 1, 2, 3, 4,	5, 6, 7, 8, 9 };  // sizeof(buf) => 10
	  void getMessage(char*	dst) {
	    memcpy(dst,	buf, sizeof(buf) / sizeof(int));  // sizeof(int) => 4  [incompatible sizes]
	  }

       In the following	example, the expression	 sizeof(Values)	 is  returning
       the  size of char*. One can easily be fooled by its declaration,	but in
       parameter declaration the size '10' is ignored and the function is  re-
       ceiving a char*.

	  char OrderedValues[10] = { 0,	1, 2, 3, 4, 5, 6, 7, 8,	9 };
	  return CompareArray(char Values[10]) {
	    return memcmp(OrderedValues, Values, sizeof(Values)) == 0;	// sizeof(Values) ==> sizeof(char*) [implicit cast to char*]
	  }

   Suspicious 'sizeof' by 'sizeof' expression
       Multiplying sizeof expressions typically	makes no sense and is probably
       a logic error. In the following example,	the programmer used *  instead
       of /.

	  const	char kMessage[]	= "Hello World!";
	  void getMessage(char*	buf) {
	    memcpy(buf,	kMessage, sizeof(kMessage) * sizeof(char));  //	 sizeof(kMessage) / sizeof(char)
	  }

       This check may trigger on code using the	arraysize macro. The following
       code is working correctly but should be simplified by  using  only  the
       sizeof operator.

	  extern Object	objects[100];
	  void InitializeObjects() {
	    memset(objects, 0, arraysize(objects) * sizeof(Object));  // sizeof(objects)
	  }

   Suspicious usage of 'sizeof(sizeof(...))'
       Getting the sizeof of a sizeof makes no sense and is typically an error
       hidden through macros.

	  #define INT_SZ sizeof(int)
	  int buf[] = {	42 };
	  void getInt(int* dst)	{
	    memcpy(dst,	buf, sizeof(INT_SZ));  // sizeof(sizeof(int)) is suspicious.
	  }

   Options
       WarnOnSizeOfConstant
	      When non-zero,  the  check  will	warn  on  an  expression  like
	      sizeof(CONSTANT).	Default	is 1.

       WarnOnSizeOfIntegerExpression
	      When  non-zero,  the  check  will	 warn  on  an  expression like
	      sizeof(expr) where the expression	results	in an integer. Default
	      is 0.

       WarnOnSizeOfThis
	      When  non-zero,  the  check  will	 warn  on  an  expression like
	      sizeof(this).  Default is	1.

       WarnOnSizeOfCompareToConstant
	      When non-zero,  the  check  will	warn  on  an  expression  like
	      sizeof(epxr)  <=	k  for a suspicious constant k while k is 0 or
	      greater than 0x8000. Default is 1.

   bugprone-string-constructor
       Finds string constructors that are suspicious and probably errors.

       A common	mistake	is to swap parameters to the  'fill'  string-construc-
       tor.

       Examples:

	  std::string str('x', 50); // should be str(50, 'x')

       Calling	the  string-literal  constructor with a	length bigger than the
       literal is suspicious and adds extra random characters to the string.

       Examples:

	  std::string("test", 200);   // Will include random characters	after "test".

       Creating	an empty string	from constructors with parameters  is  consid-
       ered  suspicious.  The  programmer should use the empty constructor in-
       stead.

       Examples:

	  std::string("test", 0);   // Creation	of an empty string.

   Options
       WarnOnLargeLength
	      When non-zero, the check will warn on a  string  with  a	length
	      greater than LargeLengthThreshold. Default is 1.

       LargeLengthThreshold
	      An  integer  specifying  the  large length threshold. Default is
	      0x800000.

   bugprone-string-integer-assignment
       The check finds assignments of an integer  to  std::basic_string<CharT>
       (std::string,  std::wstring,  etc.).  The  source of the	problem	is the
       following assignment operator of	std::basic_string<CharT>:

	  basic_string&	operator=( CharT ch );

       Numeric types can be implicitly casted to character types.

	  std::string s;
	  int x	= 5965;
	  s = 6;
	  s = x;

       Use the appropriate conversion functions	or character literals.

	  std::string s;
	  int x	= 5965;
	  s = '6';
	  s = std::to_string(x);

       In order	to suppress false positives, use an explicit cast.

	  std::string s;
	  s = static_cast<char>(6);

   bugprone-string-literal-with-embedded-nul
       Finds occurrences of string literal with	 embedded  NUL	character  and
       validates their usage.

   Invalid escaping
       Special	characters  can	 be  escaped  within a string literal by using
       their hexadecimal encoding like \x42. A common  mistake	is  to	escape
       them like this \0x42 where the \0 stands	for the	NUL character.

	  const	char* Example[]	= "Invalid character: \0x12 should be \x12";
	  const	char* Bytes[] =	"\x03\0x02\0x01\0x00\0xFF\0xFF\0xFF";

   Truncated literal
       String-like  classes  can  manipulate strings with embedded NUL as they
       are keeping track of the	bytes and the length. This is not the case for
       a char* (NUL-terminated)	string.

       A  common  mistake  is  to pass a string-literal	with embedded NUL to a
       string constructor expecting a NUL-terminated string. The  bytes	 after
       the first NUL character are truncated.

	  std::string str("abc\0def");	// "def" is truncated
	  str += "\0";			// This	statement is doing nothing
	  if (str == "\0abc") return;	// This	expression is always true

   bugprone-suspicious-enum-usage
       The  checker detects various cases when an enum is probably misused (as
       a bitmask ).

       1. When "ADD" or	"bitwise OR" is	used between two enum which come  from
	  different types and these types value	ranges are not disjoint.

       The  following cases will be investigated only using StrictMode.	We re-
       gard the	enum as	a (suspicious) bitmask if the three  conditions	 below
       are true	at the same time:

       o at  most  half	 of  the elements of the enum are non pow-of-2 numbers
	 (because of short enumerations)

       o there is another non pow-of-2 number than the	enum  constant	repre-
	 senting  all  choices	(the result "bitwise OR" operation of all enum
	 elements)

       o enum type variable/enumconstant is used as an	argument  of  a	 +  or
	 "bitwise OR " operator

       So  whenever  the  non pow-of-2 element is used as a bitmask element we
       diagnose	a misuse and give a warning.

       2. Investigating	the right hand side of += and |= operator.

       3. Check	only the enum value side of a |	and + operator if one of  them
	  is not enum val.

       4. Check	 both  side  of	| or + operator	where the enum values are from
	  the same enum	type.

       Examples:

	  enum { A, B, C };
	  enum { D, E, F = 5 };
	  enum { G = 10, H = 11, I = 12	};

	  unsigned flag;
	  flag =
	      A	|
	      H; // OK,	disjoint value intervalls in the enum types ->probably good use.
	  flag = B | F;	// Warning, have common	values so they are probably misused.

	  // Case 2:
	  enum Bitmask {
	    A =	0,
	    B =	1,
	    C =	2,
	    D =	4,
	    E =	8,
	    F =	16,
	    G =	31 // OK, real bitmask.
	  };

	  enum Almostbitmask {
	    AA = 0,
	    BB = 1,
	    CC = 2,
	    DD = 4,
	    EE = 8,
	    FF = 16,
	    GG // Problem, forgot to initialize.
	  };

	  unsigned flag	= 0;
	  flag |= E; //	OK.
	  flag |=
	      EE; // Warning at	the decl, and note that	it was used here as a bitmask.

   Options
       StrictMode
	      Default value: 0.	 When non-null the  suspicious	bitmask	 usage
	      will  be	investigated  additionally to the different enum usage
	      check.

   bugprone-suspicious-memset-usage
       This check finds	memset() calls with potential mistakes in their	 argu-
       ments.  Considering the function	as void* memset(void* destination, int
       fill_value, size_t byte_count), the following cases are covered:

       Case 1: Fill value is a character ``'0'``

       Filling up a memory area	with ASCII code	48 characters is  not  custom-
       ary, possibly integer zeroes were intended instead.  The	check offers a
       replacement of '0' with 0. Memsetting character pointers	 with  '0'  is
       allowed.

       Case 2: Fill value is truncated

       Memset  converts	 fill_value  to	 unsigned  char	 before	 using	it. If
       fill_value is out of unsigned character range, it  gets	truncated  and
       memory will not contain the desired pattern.

       Case 3: Byte count is zero

       Calling memset with a literal zero in its byte_count argument is	likely
       to be unintended	and swapped with fill_value. The check offers to  swap
       these two arguments.

       Corresponding cpplint.py	check name: runtime/memset.

       Examples:

	  void foo() {
	    int	i[5] = {1, 2, 3, 4, 5};
	    int	*ip = i;
	    char c = '1';
	    char *cp = &c;
	    int	v = 0;

	    // Case 1
	    memset(ip, '0', 1);	// suspicious
	    memset(cp, '0', 1);	// OK

	    // Case 2
	    memset(ip, 0xabcd, 1); // fill value gets truncated
	    memset(ip, 0x00, 1);   // OK

	    // Case 3
	    memset(ip, sizeof(int), v);	// zero	length,	potentially swapped
	    memset(ip, 0, 1);		// OK
	  }

   bugprone-suspicious-missing-comma
       String  literals	 placed	 side-by-side  are concatenated	at translation
       phase 6 (after the preprocessor). This feature  is  used	 to  represent
       long string literal on multiple lines.

       For instance, the following declarations	are equivalent:

	  const	char* A[] = "This is a test";
	  const	char* B[] = "This" " is	a "    "test";

       A  common  mistake done by programmers is to forget a comma between two
       string literals in an array initializer list.

	  const	char* Test[] = {
	    "line 1",
	    "line 2"	 // Missing comma!
	    "line 3",
	    "line 4",
	    "line 5"
	  };

       The array contains the string "line 2line3" at offset 1 (i.e. Test[1]).
       Clang won't generate warnings at	compile	time.

       This check may warn incorrectly on cases	like:

	  const	char* SupportedFormat[]	= {
	    "Error %s",
	    "Code " PRIu64,   // May warn here.
	    "Warning %s",
	  };

   Options
       SizeThreshold
	      An unsigned integer specifying the minimum size of a string lit-
	      eral to be considered by the check. Default is 5U.

       RatioThreshold
	      A	string specifying the maximum threshold	ratio [0, 1.0] of sus-
	      picious string literals to be considered.	Default	is ".2".

       MaxConcatenatedTokens
	      An  unsigned  integer  specifying	the maximum number of concate-
	      nated tokens.  Default is	5U.

   bugprone-suspicious-semicolon
       Finds most instances of stray semicolons	that  unexpectedly  alter  the
       meaning of the code. More specifically, it looks	for if,	while, for and
       for-range statements whose body is a single semicolon,  and  then  ana-
       lyzes  the  context of the code (e.g. indentation) in an	attempt	to de-
       termine whether that is intentional.

	  if (x	< y);
	  {
	    x++;
	  }

       Here the	body of	the if statement consists of only the semicolon	at the
       end of the first	line, and x will be incremented	regardless of the con-
       dition.

	  while	((line = readLine(file)) != NULL);
	    processLine(line);

       As a result of this code, processLine() will only be called once,  when
       the  while loop with the	empty body exits with line == NULL. The	inden-
       tation of the code indicates the	intention of the programmer.

	  if (x	>= y);
	  x -= y;

       While the indentation does not imply any	nesting, there	is  simply  no
       valid  reason  to  have	an if statement	with an	empty body (but	it can
       make sense for a	loop). So this check issues a  warning	for  the  code
       above.

       To solve	the issue remove the stray semicolon or	in case	the empty body
       is intentional, reflect this using code indentation or  put  the	 semi-
       colon in	a new line. For	example:

	  while	(readWhitespace());
	    Token t = readNextToken();

       Here  the  second  line	is  indented in	a way that suggests that it is
       meant to	be the body of the while loop -	whose body is in  fact	empty,
       because of the semicolon	at the end of the first	line.

       Either remove the indentation from the second line:

	  while	(readWhitespace());
	  Token	t = readNextToken();

       ... or move the semicolon from the end of the first line	to a new line:

	  while	(readWhitespace())
	    ;

	    Token t = readNextToken();

       In  this	 case  the check will assume that you know what	you are	doing,
       and will	not raise a warning.

   bugprone-suspicious-string-compare
       Find suspicious usage of	runtime	 string	 comparison  functions.	  This
       check is	valid in C and C++.

       Checks  for  calls  with	implicit comparator and	proposed to explicitly
       add it.

	  if (strcmp(...))	 // Implicitly compare to zero
	  if (!strcmp(...))	 // Won't warn
	  if (strcmp(...) != 0)	 // Won't warn

       Checks that compare function results  (i,e,  strcmp)  are  compared  to
       valid constant. The resulting value is

	  <  0	  when lower than,
	  >  0	  when greater than,
	  == 0	  when equals.

       A common	mistake	is to compare the result to 1 or -1.

	  if (strcmp(...) == -1)  // Incorrect usage of	the returned value.

       Additionally,  the  check warns if the results value is implicitly cast
       to a suspicious non-integer type.  It's	happening  when	 the  returned
       value is	used in	a wrong	context.

	  if (strcmp(...) < 0.)	 // Incorrect usage of the returned value.

   Options
       WarnOnImplicitComparison
	      When  non-zero, the check	will warn on implicit comparison. 1 by
	      default.

       WarnOnLogicalNotComparison
	      When non-zero, the check will warn on logical not	comparison.  0
	      by default.

       StringCompareLikeFunctions
	      A	 string	 specifying  the  comma-separated  names  of the extra
	      string comparison	functions. Default is an  empty	 string.   The
	      check  will  detect  the	following string comparison functions:
	      __builtin_memcmp,	   __builtin_strcasecmp,     __builtin_strcmp,
	      __builtin_strncasecmp,  __builtin_strncmp,  _mbscmp,  _mbscmp_l,
	      _mbsicmp,	_mbsicmp_l, _mbsnbcmp, _mbsnbcmp_l,  _mbsnbicmp,  _mb-
	      snbicmp_l,   _mbsncmp,   _mbsncmp_l,   _mbsnicmp,	  _mbsnicmp_l,
	      _memicmp,	_memicmp_l,  _stricmp,	_stricmp_l,  _strnicmp,	 _str-
	      nicmp_l,	_wcsicmp, _wcsicmp_l, _wcsnicmp, _wcsnicmp_l, lstrcmp,
	      lstrcmpi,	memcmp,	memicmp, strcasecmp, strcmp, strcmpi, stricmp,
	      strncasecmp, strncmp, strnicmp, wcscasecmp, wcscmp, wcsicmp, wc-
	      sncmp, wcsnicmp, wmemcmp.

   bugprone-swapped-arguments
       Finds potentially swapped arguments by looking at implicit conversions.

   bugprone-terminating-continue
       Detects do while	loops with a condition always evaluating to false that
       have  a continue	statement, as this continue terminates the loop	effec-
       tively.

	  void f() {
	  do {
		// some	code
	    continue; // terminating continue
	    // some other code
	  } while(false);

   bugprone-throw-keyword-missing
       Warns about a potentially missing throw keyword.	If a temporary	object
       is  created,  but  the object's type derives from (or is	the same as) a
       class that has 'EXCEPTION', 'Exception' or 'exception' in its name,  we
       can assume that the programmer's	intention was to throw that object.

       Example:

	  void f(int i)	{
	    if (i < 0) {
	      // Exception is created but is not thrown.
	      std::runtime_error("Unexpected argument");
	    }
	  }

   bugprone-too-small-loop-variable
       Detects	those  for  loops that have a loop variable with a "too	small"
       type which means	this type can't	represent all values which are part of
       the iteration range.

	  int main() {
	    long size =	294967296l;
	    for	(short i = 0; i	< size;	++i) {}
	  }

       This  for  loop is an infinite loop because the short type can't	repre-
       sent all	values in the [0..size]	interval.

       In a real use case size means a container's size	which depends  on  the
       user input.

	  int doSomething(const	std::vector& items) {
	    for	(short i = 0; i	< items.size();	++i) {}
	  }

       This  algorithm	works  for  small  amount of objects, but will lead to
       freeze for a a larger user input.

       MagnitudeBitsUpperLimit
	      Upper limit for the magnitude bits of the	loop variable. If it's
	      set  the check filters out those catches in which	the loop vari-
	      able's type has more  magnitude  bits  as	 the  specified	 upper
	      limit.  The  default value is 16.	 For example, if the user sets
	      this option to 31	(bits),	then a 32-bit unsigend int is  ignored
	      by  the  check, however a	32-bit int is not (A 32-bit signed int
	      has 31 magnitude bits).

	  int main() {
	    long size =	294967296l;
	    for	(unsigned i = 0; i < size; ++i)	{} // no warning with MagnitudeBitsUpperLimit =	31 on a	system where unsigned is 32-bit
	    for	(int i = 0; i <	size; ++i) {} // warning with MagnitudeBitsUpperLimit =	31 on a	system where int is 32-bit
	  }

   bugprone-undefined-memory-manipulation
       Finds calls of memory manipulation  functions  memset(),	 memcpy()  and
       memmove()  on  not TriviallyCopyable objects resulting in undefined be-
       havior.

   bugprone-undelegated-constructor
       Finds creation of temporary objects in constructors that	 look  like  a
       function	call to	another	constructor of the same	class.

       The  user  most	likely	meant  to use a	delegating constructor or base
       class initializer.

   bugprone-unhandled-self-assignment
       cert-oop54-cpp redirects	here as	an alias for this check. For the  CERT
       alias, the WarnOnlyIfThisHasSuspiciousField option is set to 0.

       Finds  user-defined  copy assignment operators which do not protect the
       code against self-assignment either by checking self-assignment explic-
       itly or using the copy-and-swap or the copy-and-move method.

       By  default,  this  check  searches  only  those	classes	which have any
       pointer or C array field	to avoid false positives. In case of a pointer
       or  a  C	array, it's likely that	self-copy assignment breaks the	object
       if the copy assignment operator was not written with care.

       See also: OOP54-CPP. Gracefully handle self-copy	assignment

       A copy assignment operator must prevent that self-copy assignment ruins
       the  object  state.  A typical use case is when the class has a pointer
       field and the copy assignment operator first releases the  pointed  ob-
       ject and	then tries to assign it:

	  class	T {
	  int* p;

	  public:
	    T(const T &rhs) : p(rhs.p ?	new int(*rhs.p)	: nullptr) {}
	    ~T() { delete p; }

	    // ...

	    T& operator=(const T &rhs) {
	      delete p;
	      p	= new int(*rhs.p);
	      return *this;
	    }
	  };

       There  are  two common C++ patterns to avoid this problem. The first is
       the self-assignment check:

	  class	T {
	  int* p;

	  public:
	    T(const T &rhs) : p(rhs.p ?	new int(*rhs.p)	: nullptr) {}
	    ~T() { delete p; }

	    // ...

	    T& operator=(const T &rhs) {
	      if(this == &rhs)
		return *this;

	      delete p;
	      p	= new int(*rhs.p);
	      return *this;
	    }
	  };

       The second one is the copy-and-swap method when we create  a  temporary
       copy  (using  the copy constructor) and then swap this temporary	object
       with this:

	  class	T {
	  int* p;

	  public:
	    T(const T &rhs) : p(rhs.p ?	new int(*rhs.p)	: nullptr) {}
	    ~T() { delete p; }

	    // ...

	    void swap(T	&rhs) {
	      using std::swap;
	      swap(p, rhs.p);
	    }

	    T& operator=(const T &rhs) {
	      T(rhs).swap(*this);
	      return *this;
	    }
	  };

       There is	a third	pattern	which  is  less	 common.  Let's	 call  it  the
       copy-and-move  method  when  we create a	temporary copy (using the copy
       constructor) and	then move this temporary object	 into  this  (needs  a
       move assignment operator):

	  class	T {
	  int* p;

	  public:
	    T(const T &rhs) : p(rhs.p ?	new int(*rhs.p)	: nullptr) {}
	    ~T() { delete p; }

	    // ...

	    T& operator=(const T &rhs) {
	      T	t = rhs;
	      *this = std::move(t);
	      return *this;
	    }

	    T& operator=(T &&rhs) {
	      p	= rhs.p;
	      rhs.p = nullptr;
	      return *this;
	    }
	  };

       WarnOnlyIfThisHasSuspiciousField
	      When  non-zero,  the check will warn only	if the container class
	      of the  copy  assignment	operator  has  any  suspicious	fields
	      (pointer or C array). This option	is set to 1 by default.

   bugprone-unused-raii
       Finds temporaries that look like	RAII objects.

       The canonical example for this is a scoped lock.

	  {
	    scoped_lock(&global_mutex);
	    critical_section();
	  }

       The destructor of the scoped_lock is called before the critical_section
       is entered, leaving it unprotected.

       We apply	a number of heuristics to reduce the false positive  count  of
       this check:

       o Ignore	 code  expanded	from macros. Testing frameworks	make heavy use
	 of this.

       o Ignore	types with trivial destructors.	They are very unlikely	to  be
	 RAII objects and there's no difference	when they are deleted.

       o Ignore	objects	at the end of a	compound statement (doesn't change be-
	 havior).

       o Ignore	objects	returned from a	call.

   bugprone-unused-return-value
       Warns on	unused function	return values. The  checked  funtions  can  be
       configured.

   Options
       CheckedFunctions
	      Semicolon-separated  list	 of  functions	to  check. Defaults to
	      ::std::async;::std::launder;::std::remove;::std::re-
	      move_if;::std::unique;::std::unique_ptr::release;::std::ba-
	      sic_string::empty;::std::vector::empty.	This  means  that  the
	      calls to following functions are checked by default:

	      o	std::async().  Not  using the return value makes the call syn-
		chronous.

	      o	std::launder().	Not using the return value usually means  that
		the  function  interface  was misunderstood by the programmer.
		Only the returned pointer is "laundered", not the argument.

	      o	std::remove(), std::remove_if()	 and  std::unique().  The  re-
		turned	iterator  indicates  the  boundary between elements to
		keep and elements to be	removed. Not using  the	 return	 value
		means  that  the information about which elements to remove is
		lost.

	      o	std::unique_ptr::release(). Not	using  the  return  value  can
		lead  to  resource leaks if the	same pointer isn't stored any-
		where else. Often, ignoring the	release() return  value	 indi-
		cates that the programmer confused the function	with reset().

	      o	std::basic_string::empty() and std::vector::empty(). Not using
		the return value often indicates that the programmer  confused
		the function with clear().

   bugprone-use-after-move
       Warns if	an object is used after	it has been moved, for example:

	  std::string str = "Hello, world!\n";
	  std::vector<std::string> messages;
	  messages.emplace_back(std::move(str));
	  std::cout << str;

       The last	line will trigger a warning that str is	used after it has been
       moved.

       The check does not trigger a warning if the object is reinitialized af-
       ter the move and	before the use.	For example, no	warning	will be	output
       for this	code:

	  messages.emplace_back(std::move(str));
	  str =	"Greetings, stranger!\n";
	  std::cout << str;

       The check takes control flow into account. A warning is only emitted if
       the  use	 can  be  reached from the move. This means that the following
       code does not produce a warning:

	  if (condition) {
	    messages.emplace_back(std::move(str));
	  } else {
	    std::cout << str;
	  }

       On the other hand, the following	code does produce a warning:

	  for (int i = 0; i < 10; ++i) {
	    std::cout << str;
	    messages.emplace_back(std::move(str));
	  }

       (The use-after-move happens on the second iteration of the loop.)

       In some cases, the check	may not	be able	to detect  that	 two  branches
       are mutually exclusive. For example (assuming that i is an int):

	  if (i	== 1) {
	    messages.emplace_back(std::move(str));
	  }
	  if (i	== 2) {
	    std::cout << str;
	  }

       In this case, the check will erroneously	produce	a warning, even	though
       it is not possible for both the move and	the use	to be executed.

       An erroneous warning can	be silenced by reinitializing the object after
       the move:

	  if (i	== 1) {
	    messages.emplace_back(std::move(str));
	    str	= "";
	  }
	  if (i	== 2) {
	    std::cout << str;
	  }

       Subsections below explain more precisely	what exactly the check consid-
       ers to be a move, use, and reinitialization.

   Unsequenced moves, uses, and	reinitializations
       In many cases, C++ does not make	any  guarantees	 about	the  order  in
       which  sub-expressions of a statement are evaluated. This means that in
       code like the following,	it is not guaranteed whether the use will hap-
       pen before or after the move:

	  void f(int i,	std::vector<int> v);
	  std::vector<int> v = { 1, 2, 3 };
	  f(v[1], std::move(v));

       In  this	 kind  of situation, the check will note that the use and move
       are unsequenced.

       The check will also take	sequencing rules into account when  reinitial-
       izations	 occur in the same statement as	moves or uses. A reinitializa-
       tion is only considered to reinitialize a variable if it	is  guaranteed
       to be evaluated after the move and before the use.

   Move
       The  check  currently  only considers calls of std::move	on local vari-
       ables or	function parameters. It	does not check moves of	 member	 vari-
       ables or	global variables.

       Any  call  of  std::move	on a variable is considered to cause a move of
       that variable, even if the result of std::move  is  not	passed	to  an
       rvalue reference	parameter.

       This  means  that  the  check will flag a use-after-move	even on	a type
       that does not define a move constructor or  move	 assignment  operator.
       This  is	 intentional.	Developers may use std::move on	such a type in
       the expectation that the	type will add move semantics in	the future. If
       such  a	std::move has the potential to cause a use-after-move, we want
       to warn about it	even if	the type does  not  implement  move  semantics
       yet.

       Furthermore,  if	 the result of std::move is passed to an rvalue	refer-
       ence parameter, this will always	be considered to cause a move, even if
       the  function that consumes this	parameter does not move	from it, or if
       it does so only conditionally. For example, in the following situation,
       the check will assume that a move always	takes place:

	  std::vector<std::string> messages;
	  void f(std::string &&str) {
	    // Only remember the message if it isn't empty.
	    if (!str.empty()) {
	      messages.emplace_back(std::move(str));
	    }
	  }
	  std::string str = "";
	  f(std::move(str));

       The check will assume that the last line	causes a move, even though, in
       this particular case, it	does not. Again, this is intentional.

       When analyzing the order	in which  moves,  uses	and  reinitializations
       happen  (see  section  Unsequenced moves, uses, and reinitializations),
       the move	is assumed to occur in whichever function the  result  of  the
       std::move is passed to.

   Use
       Any  occurrence	of  the	 moved variable	that is	not a reinitialization
       (see below) is considered to be a use.

       An  exception  to   this	  are	objects	  of   type   std::unique_ptr,
       std::shared_ptr	and  std::weak_ptr,  which  have defined move behavior
       (objects	of these classes are guaranteed	to be empty  after  they  have
       been  moved  from).  Therefore, an object of these classes will only be
       considered to be	used if	it is dereferenced, i.e. if operator*,	opera-
       tor-> or	operator[] (in the case	of std::unique_ptr<T []>) is called on
       it.

       If multiple uses	occur after  a	move,  only  the  first	 of  these  is
       flagged.

   Reinitialization
       The  check  considers  a	 variable to be	reinitialized in the following
       cases:

	  o The	variable occurs	on the left-hand side of an assignment.

	  o The	variable is passed to a	function as  a	non-const  pointer  or
	    non-const  lvalue  reference. (It is assumed that the variable may
	    be an out-parameter	for the	function.)

	  o clear() or assign()	is called on the variable and the variable  is
	    of	one  of	 the  standard	container  types basic_string, vector,
	    deque, forward_list,  list,	 set,  map,  multiset,	multimap,  un-
	    ordered_set,   unordered_map,  unordered_multiset,	unordered_mul-
	    timap.

	  o reset() is called on the variable and  the	variable  is  of  type
	    std::unique_ptr, std::shared_ptr or	std::weak_ptr.

	  o A  member function marked with the [[clang::reinitializes]]	attri-
	    bute is called on the variable.

       If the variable in question is a	struct and an individual member	 vari-
       able  of	that struct is written to, the check does not consider this to
       be a reinitialization --	even if, eventually, all member	 variables  of
       the struct are written to. For example:

	  struct S {
	    std::string	str;
	    int	i;
	  };
	  S s =	{ "Hello, world!\n", 42	};
	  S s_other = std::move(s);
	  s.str	= "Lorem ipsum";
	  s.i =	99;

       The  check will not consider s to be reinitialized after	the last line;
       instead,	the line that assigns to s.str will be flagged	as  a  use-af-
       ter-move.   This	 is  intentional  as  this pattern of reinitializing a
       struct is error-prone.  For example, if an additional  member  variable
       is  added  to  S,  it is	easy to	forget to add the reinitialization for
       this additional member. Instead,	it is safer to assign  to  the	entire
       struct in one go, and this will also avoid the use-after-move warning.

   bugprone-virtual-near-miss
       Warn if a function is a near miss (ie. the name is very similar and the
       function	signiture is the same) to  a  virtual  function	 from  a  base
       class.

       Example:

	  struct Base {
	    virtual void func();
	  };

	  struct Derived : Base	{
	    virtual funk();
	    // warning:	'Derived::funk'	has a similar name and the same	signature as virtual method 'Base::func'; did you mean to override it?
	  };

   cert-dcl03-c
       The  cert-dcl03-c  check	is an alias, please see	misc-static-assert for
       more information.

   cert-dcl16-c
       The    cert-dcl16-c    check    is     an     alias,	please	   see
       readability-uppercase-literal-suffix for	more information.

   cert-dcl21-cpp
       This  check flags postfix operator++ and	operator-- declarations	if the
       return type is not a const object. This also warns if the  return  type
       is a reference type.

       The  object  returned  by  a postfix increment or decrement operator is
       supposed	to be a	snapshot of the	object's value prior to	 modification.
       With  such  an  implementation, any modifications made to the resulting
       object from calling operator++(int) would be modifying a	temporary  ob-
       ject.  Thus, such an implementation of a	postfix	increment or decrement
       operator	should instead return a	const object,  prohibiting  accidental
       mutation	 of  a	temporary object.  Similarly, it is unexpected for the
       postfix operator	to return a reference to its previous state,  and  any
       subsequent modifications	would be operating on a	stale object.

       This  check  corresponds	to the CERT C++	Coding Standard	recommendation
       DCL21-CPP. Overloaded postfix increment and decrement operators	should
       return  a  const	 object. However, all of the CERT recommendations have
       been removed from public	view, and so their justification for  the  be-
       havior of this check requires an	account	on their wiki to view.

   cert-dcl50-cpp
       This  check  flags  all	function definitions (but not declarations) of
       C-style variadic	functions.

       This check corresponds to the CERT C++ Coding Standard rule  DCL50-CPP.
       Do not define a C-style variadic	function.

   cert-dcl54-cpp
       The     cert-dcl54-cpp	  check	   is	 an    alias,	 please	   see
       misc-new-delete-overloads for more information.

   cert-dcl58-cpp
       Modification of the std or posix	namespace can result in	undefined  be-
       havior.	This check warns for such modifications.

       Examples:

	  namespace std	{
	    int	x; // May cause	undefined behavior.
	  }

       This  check corresponds to the CERT C++ Coding Standard rule DCL58-CPP.
       Do not modify the standard namespaces.

   cert-dcl59-cpp
       The    cert-dcl59-cpp	check	 is    an    alias,	please	   see
       google-build-namespaces for more	information.

   cert-env33-c
       This  check  flags calls	to system(), popen(), and _popen(), which exe-
       cute a command processor. It does not flag calls	 to  system()  with  a
       null pointer argument, as such a	call checks for	the presence of	a com-
       mand processor but does not actually attempt to execute a command.

       This check corresponds to the CERT C Coding Standard rule  ENV33-C.  Do
       not call	system().

   cert-err09-cpp
       The     cert-err09-cpp	  check	   is	 an    alias,	 please	   see
       misc-throw-by-value-catch-by-reference for more information.

       This check corresponds to the CERT C++ Coding  Standard	recommendation
       ERR09-CPP. Throw	anonymous temporaries. However,	all of the CERT	recom-
       mendations have been removed from public	view, and so their  justifica-
       tion  for  the behavior of this check requires an account on their wiki
       to view.

   cert-err34-c
       This check flags	calls to string-to-number conversion functions that do
       not  verify  the	validity of the	conversion, such as atoi() or scanf().
       It does not flag	calls to strtol(), or other, related conversion	 func-
       tions that do perform better error checking.

	  #include <stdlib.h>

	  void func(const char *buff) {
	    int	si;

	    if (buff) {
	      si = atoi(buff); /* 'atoi' used to convert a string to an	integer, but function will
				   not report conversion errors; consider using	'strtol' instead. */
	    } else {
	      /* Handle	error */
	    }
	  }

       This  check corresponds to the CERT C Coding Standard rule ERR34-C. De-
       tect errors when	converting a string to a number.

   cert-err52-cpp
       This check flags	all call expressions involving setjmp()	and longjmp().

       This check corresponds to the CERT C++ Coding Standard rule  ERR52-CPP.
       Do not use setjmp() or longjmp().

   cert-err58-cpp
       This check flags	all static or thread_local variable declarations where
       the initializer for the object may throw	an exception.

       This check corresponds to the CERT C++ Coding Standard rule  ERR58-CPP.
       Handle all exceptions thrown before main() begins executing.

   cert-err60-cpp
       This  check  flags  all throw expressions where the exception object is
       not nothrow copy	constructible.

       This check corresponds to the CERT C++ Coding Standard rule  ERR60-CPP.
       Exception objects must be nothrow copy constructible.

   cert-err61-cpp
       The     cert-err61-cpp	  check	   is	 an    alias,	 please	   see
       misc-throw-by-value-catch-by-reference for more information.

   cert-fio38-c
       The    cert-fio38-c    check    is     an     alias,	please	   see
       misc-non-copyable-objects for more information.

   cert-flp30-c
       This  check flags for loops where the induction expression has a	float-
       ing-point type.

       This check corresponds to the CERT C Coding Standard rule  FLP30-C.  Do
       not use floating-point variables	as loop	counters.

   cert-msc30-c
       The  cert-msc30-c check is an alias, please see cert-msc50-cpp for more
       information.

   cert-msc32-c
       The cert-msc32-c	check is an alias, please see cert-msc51-cpp for  more
       information.

   cert-msc50-cpp
       Pseudorandom number generators use mathematical algorithms to produce a
       sequence	of numbers with	good statistical properties, but  the  numbers
       produced	 are  not  genuinely  random. The std::rand() function takes a
       seed (number), runs a mathematical operation on it and returns the  re-
       sult.  By  manipulating	the  seed  the result can be predictable. This
       check warns for the usage of std::rand().

   cert-msc51-cpp
       This check flags	all pseudo-random number engines, engine  adaptor  in-
       stantiations  and srand() when initialized or seeded with default argu-
       ment, constant expression or any	user-configurable type.	 Pseudo-random
       number  engines	seeded with a predictable value	may cause vulnerabili-
       ties e.g. in security protocols.	 This is a  CERT  security  rule,  see
       MSC51-CPP.  Ensure  your	random number generator	is properly seeded and
       MSC32-C.	Properly seed pseudorandom number generators.

       Examples:

	  void foo() {
	    std::mt19937 engine1; // Diagnose, always generate the same	sequence
	    std::mt19937 engine2(1); //	Diagnose
	    engine1.seed(); // Diagnose
	    engine2.seed(1); //	Diagnose

	    std::time_t	t;
	    engine1.seed(std::time(&t)); // Diagnose, system time might	be controlled by user

	    int	x = atoi(argv[1]);
	    std::mt19937 engine3(x);  // Will not warn
	  }

   Options
       DisallowedSeedTypes
	      A	comma-separated	list of	the type names which  are  disallowed.
	      Default values are time_t, std::time_t.

   cert-oop11-cpp
       The     cert-oop11-cpp	  check	   is	 an    alias,	 please	   see
       performance-move-constructor-init for more information.

       This check corresponds to the CERT C++ Coding  Standard	recommendation
       OOP11-CPP.  Do  not copy-initialize members or base classes from	a move
       constructor. However, all of the	CERT recommendations have been removed
       from  public  view, and so their	justification for the behavior of this
       check requires an account on their wiki to view.

   cert-oop54-cpp
       The    cert-oop54-cpp	check	 is    an    alias,	please	   see
       bugprone-unhandled-self-assignment for more information.

   cppcoreguidelines-avoid-c-arrays
       The  cppcoreguidelines-avoid-c-arrays  check  is	 an  alias, please see
       modernize-avoid-c-arrays	for more information.

   cppcoreguidelines-avoid-goto
       The usage of goto for control flow is error prone  and  should  be  re-
       placed  with looping constructs.	Only forward jumps in nested loops are
       accepted.

       This check implements ES.76 from	the CppCoreGuidelines and  6.3.1  from
       High Integrity C++.

       For more	information on why to avoid programming	with goto you can read
       the famous paper	A Case against the GO TO Statement..

       The check diagnoses goto	for backward jumps  in	every  language	 mode.
       These should be replaced	with C/C++ looping constructs.

	  // Bad, handwritten for loop.
	  int i	= 0;
	  // Jump label	for the	loop
	  loop_start:
	  do_some_operation();

	  if (i	< 100) {
	    ++i;
	    goto loop_start;
	  }

	  // Better
	  for(int i = 0; i < 100; ++i)
	    do_some_operation();

       Modern C++ needs	goto only to jump out of nested	loops.

	  for(int i = 0; i < 100; ++i) {
	    for(int j =	0; j < 100; ++j) {
	      if (i * j	> 500)
		goto early_exit;
	    }
	  }

	  early_exit:
	  some_operation();

       All other uses of goto are diagnosed in C++.

   cppcoreguidelines-avoid-magic-numbers
       The cppcoreguidelines-avoid-magic-numbers check is an alias, please see
       readability-magic-numbers for more information.

   cppcoreguidelines-c-copy-assignment-signature
       The cppcoreguidelines-c-copy-assignment-signature check	is  an	alias,
       please see misc-unconventional-assign-operator for more information.

   cppcoreguidelines-explicit-virtual-functions
       The  cppcoreguidelines-explicit-virtual-functions  check	 is  an	alias,
       please see modernize-use-override for more information.

   cppcoreguidelines-interfaces-global-init
       This check flags	initializers of	globals	that  access  extern  objects,
       and therefore can lead to order-of-initialization problems.

       This  rule  is  part of the "Interfaces"	profile	of the C++ Core	Guide-
       lines,								   see
       https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#Ri-global-init

       Note that currently this	does not flag  calls  to  non-constexpr	 func-
       tions,  and  therefore  globals	could still be accessed	from functions
       themselves.

   cppcoreguidelines-macro-usage
       Finds macro usage that is considered problematic	 because  better  lan-
       guage constructs	exist for the task.

       The  relevant  sections	in  the	C++ Core Guidelines are	Enum.1,	ES.30,
       ES.31 and ES.33.

   Options
       AllowedRegexp
	      A	regular	expression to filter allowed macros. For  example  DE-
	      BUG*|LIBTORRENT*|TORRENT*|UNI*   could   be  applied  to	filter
	      libtorrent.  Default value is ^DEBUG_*.

       CheckCapsOnly
	      Boolean flag to warn on all macros except	those  with  CAPS_ONLY
	      names.   This  option  is	 intended to ease introduction of this
	      check into older code bases. Default value is 0/false.

       IgnoreCommandLineMacros
	      Boolean flag to  toggle  ignoring	 command-line-defined  macros.
	      Default value is 1/true.

   cppcoreguidelines-narrowing-conversions
       Checks  for  silent  narrowing  conversions, e.g: int i = 0; i += 0.1;.
       While the issue is obvious in this former example, it might not	be  so
       in the following: void MyClass::f(double	d) { int_member_ += d; }.

       This  rule  is  part of the "Expressions	and statements"	profile	of the
       C++ Core	Guidelines, corresponding to rule ES.46. See

       https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#es46-avoid-lossy-narrowing-truncating-arithmetic-conversions.

       We  enforce only	part of	the guideline, more specifically, we flag nar-
       rowing conversions from:

	      o	an integer to a	narrower integer (e.g. char to unsigned	char),

	      o	an integer to a	 narrower  floating-point  (e.g.  uint64_t  to
		float),

	      o	a floating-point to an integer (e.g. double to int),

	      o	a  floating-point to a narrower	floating-point (e.g. double to
		float)	if  WarnOnFloatingPointNarrowingConversion  Option  is
		set.

       This check will flag:

	      o	All  narrowing	conversions that are not marked	by an explicit
		cast (c-style or static_cast). For example: int	i =  0;	 i  +=
		0.1;, void f(int); f(0.1);,

	      o	All  applications of binary operators with a narrowing conver-
		sions.	For example: int i; i+=	0.1;.

   Options
       WarnOnFloatingPointNarrowingConversion
	      When non-zero, the check will warn on narrowing  floating	 point
	      conversion (e.g. double to float). 1 by default.

       PedanticMode
	      When non-zero, the check will warn on assigning a	floating point
	      constant to an integer value even	if the floating	point value is
	      exactly  representable  in  the  destination  type (e.g. int i =
	      1.0;).  0	by default.

   FAQ
	  o What does "narrowing conversion from 'int' to 'float'" mean?

       An IEEE754 Floating Point number	can represent all  integer  values  in
       the  range  [-2^PrecisionBits,  2^PrecisionBits]	where PrecisionBits is
       the number of bits in the mantissa.

       For float this would be [-2^23, 2^23], where int	can  represent	values
       in the range [-2^31, 2^31-1].

	  o What does "implementation-defined" mean?

       You  may	have encountered messages like "narrowing conversion from 'un-
       signed int' to signed type 'int'	is implementation-defined".  The C/C++
       standard	 does not mandate twoas	complement for signed integers,	and so
       the compiler is free to define what the semantics are for converting an
       unsigned	 integer  to  signed  integer. Clang's implementation uses the
       twoas complement	format.

   cppcoreguidelines-no-malloc
       This check handles C-Style memory management using malloc(), realloc(),
       calloc()	 and  free().  It warns	about its use and tries	to suggest the
       use of an appropriate RAII object.  Furthermore,	it can	be  configured
       to  check  against a user-specified list	of functions that are used for
       memory management (e.g. posix_memalign()).  See C++ Core	Guidelines.

       There is	no attempt made	to provide fix-it hints, since manual resource
       management isn't	easily transformed automatically into RAII.

	  // Warns each	of the following lines.
	  // Containers	like std::vector or std::string	should be used.
	  char*	some_string = (char*) malloc(sizeof(char) * 20);
	  char*	some_string = (char*) realloc(sizeof(char) * 30);
	  free(some_string);

	  int* int_array = (int*) calloc(30, sizeof(int));

	  // Rather use	a smartpointer or stack	variable.
	  struct some_struct* s	= (struct some_struct*)	malloc(sizeof(struct some_struct));

   Options
       Allocations
	      Semicolon-separated  list	of fully qualified names of memory al-
	      location functions.  Defaults to ::malloc;::calloc.

       Deallocations
	      Semicolon-separated list of fully	qualified names	of memory  al-
	      location functions.  Defaults to ::free.

       Reallocations
	      Semicolon-separated  list	of fully qualified names of memory al-
	      location functions.  Defaults to ::realloc.

   cppcoreguidelines-non-private-member-variables-in-classes
       The cppcoreguidelines-non-private-member-variables-in-classes check  is
       an  alias,  please see misc-non-private-member-variables-in-classes for
       more information.

   cppcoreguidelines-owning-memory
       This check implements the type-based semantics of gsl::owner<T*>, which
       allows  static  analysis	 on code, that uses raw	pointers to handle re-
       sources like dynamic memory, but	won't introduce	RAII concepts.

       The relevant sections in	the C++	Core Guidelines	are  I.11,  C.33,  R.3
       and GSL.Views The definition of a gsl::owner<T*>	is straight forward

	  namespace gsl	{ template <typename T>	owner =	T; }

       It is therefore simple to introduce the owner even without using	an im-
       plementation of the Guideline Support Library.

       All checks are purely type based	and not	(yet) flow sensitive.

       The following examples will demonstrate the correct and incorrect  ini-
       tializations  of	 owners, assignment is handled the same	way. Note that
       both new	and malloc()-like resource functions are considered to produce
       resources.

	  // Creating an owner with factory functions is checked.
	  gsl::owner<int*> function_that_returns_owner() { return gsl::owner<int*>(new int(42)); }

	  // Dynamic memory must be assigned to	an owner
	  int* Something = new int(42);	// BAD,	will be	caught
	  gsl::owner<int*> Owner = new int(42);	// Good
	  gsl::owner<int*> Owner = new int[42];	// Good	as well

	  // Returned owner must be assigned to	an owner
	  int* Something = function_that_returns_owner(); // Bad, factory function
	  gsl::owner<int*> Owner = function_that_returns_owner(); // Good, result lands	in owner

	  // Something not a resource or owner should not be assigned to owners
	  int Stack = 42;
	  gsl::owner<int*> Owned = &Stack; // Bad, not a resource assigned

       In  the	case  of dynamic memory	as resource, only gsl::owner<T*> vari-
       ables are allowed to be deleted.

	  // Example Bad, non-owner as resource	handle,	will be	caught.
	  int* NonOwner	= new int(42); // First	warning	here, since new	must land in an	owner
	  delete NonOwner; // Second warning here, since only owners are allowed to be deleted

	  // Example Good, Ownership correctly stated
	  gsl::owner<int*> Owner = new int(42);	// Good
	  delete Owner;	// Good	as well, statically enforced, that only	owners get deleted

       The check will  furthermore  ensure,  that  functions,  that  expect  a
       gsl::owner<T*> as argument get called with either a gsl::owner<T*> or a
       newly created resource.

	  void expects_owner(gsl::owner<int*> o) { delete o; }

	  // Bad Code
	  int NonOwner = 42;
	  expects_owner(&NonOwner); // Bad, will get caught

	  // Good Code
	  gsl::owner<int*> Owner = new int(42);
	  expects_owner(Owner);	// Good
	  expects_owner(new int(42)); // Good as well, recognized created resource

	  // Port legacy code for better resource-safety
	  gsl::owner<FILE*> File = fopen("my_file.txt",	"rw+");
	  FILE*	BadFile	= fopen("another_file.txt", "w"); // Bad, warned

	  // ... use the file

	  fclose(File);	// Ok, File is annotated as 'owner<>'
	  fclose(BadFile); // BadFile is not an	'owner<>', will	be warned

   Options
       LegacyResourceProducers
	      Semicolon-separated list of  fully  qualified  names  of	legacy
	      functions	  that	 create	  resources   but   cannot   introduce
	      gsl::owner<>.   Defaults	 to   ::malloc;::aligned_alloc;::real-
	      loc;::calloc;::fopen;::freopen;::tmpfile.

       LegacyResourceConsumers
	      Semicolon-separated  list	 of  fully  qualified  names of	legacy
	      functions	expecting resource owners  as  pointer	arguments  but
	      cannot   introduce  gsl::owner<>.	  Defaults  to	::free;::real-
	      loc;::freopen;::fclose.

   Limitations
       Using gsl::owner<T*> in a typedef or alias is not handled correctly.

	  using	heap_int = gsl::owner<int*>;
	  heap_int allocated = new int(42); // False positive!

       The gsl::owner<T*> is declared as a templated type alias.  In  template
       functions  and  classes,	 like in the example below, the	information of
       the type	aliases	gets lost. Therefore using gsl::owner<T*> in  a	 heavy
       templated code base might lead to false positives.

       Known code constructs that do not get diagnosed correctly are:

       o std::exchange

       o std::vector<gsl::owner<T*>>

	  // This template function works as expected. Type information	doesn't	get lost.
	  template <typename T>
	  void delete_owner(gsl::owner<T*> owned_object) {
	    delete owned_object; // Everything alright
	  }

	  gsl::owner<int*> function_that_returns_owner() { return gsl::owner<int*>(new int(42)); }

	  // Type deduction does not work for auto variables.
	  // This is caught by the check and will be noted accordingly.
	  auto OwnedObject = function_that_returns_owner(); // Type of OwnedObject will	be int*

	  // Problematic function template that	looses the typeinformation on owner
	  template <typename T>
	  void bad_template_function(T some_object) {
	    // This line will trigger the warning, that	a non-owner is assigned	to an owner
	    gsl::owner<T*> new_owner = some_object;
	  }

	  // Calling the function with an owner	still yields a false positive.
	  bad_template_function(gsl::owner<int*>(new int(42)));

	  // The same issue occurs with	templated classes like the following.
	  template <typename T>
	  class	OwnedValue {
	  public:
	    const T getValue() const { return _val; }
	  private:
	    T _val;
	  };

	  // Code, that	yields a false positive.
	  OwnedValue<gsl::owner<int*>> Owner(new int(42)); // Type deduction yield T ->	int *
	  // False positive, getValue returns int* and not gsl::owner<int*>
	  gsl::owner<int*> OwnedInt = Owner.getValue();

       Another limitation of the current implementation	is only	the type based
       checking.  Suppose you have code	like the following:

	  // Two owners	with assigned resources
	  gsl::owner<int*> Owner1 = new	int(42);
	  gsl::owner<int*> Owner2 = new	int(42);

	  Owner2 = Owner1; // Conceptual Leak of initial resource of Owner2!
	  Owner1 = nullptr;

       The semantic of a gsl::owner<T*>	is mostly like	a  std::unique_ptr<T>,
       therefore  assignment of	two gsl::owner<T*> is considered a move, which
       requires	that the resource Owner2 must have been	 released  before  the
       assignment.   This kind of condition could be catched in	later improve-
       ments of	this check with	flowsensitive analysis.	Currently,  the	 Clang
       Static  Analyzer	 catches this bug for dynamic memory, but not for gen-
       eral types of resources.

   cppcoreguidelines-pro-bounds-array-to-pointer-decay
       This check flags	all array to pointer decays.

       Pointers	should not be used as arrays.  span<T>	is  a  bounds-checked,
       safe alternative	to using pointers to access arrays.

       This rule is part of the	"Bounds	safety"	profile	of the C++ Core	Guide-
       lines,								   see
       https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#Pro-bounds-decay.

   cppcoreguidelines-pro-bounds-constant-array-index
       This check flags	all array subscript expressions	on static  arrays  and
       std::arrays that	either do not have a constant integer expression index
       or are out of bounds (for std::array). For  out-of-bounds  checking  of
       static arrays, see the -Warray-bounds Clang diagnostic.

       This rule is part of the	"Bounds	safety"	profile	of the C++ Core	Guide-
       lines,								   see
       https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#Pro-bounds-arrayindex.

   Options
       GslHeader
	      The check	can generate fixes after this option has been  set  to
	      the  name	 of  the  include  file	 that contains gsl::at(), e.g.
	      "gsl/gsl.h".

       IncludeStyle
	      A	string specifying which	include-style is used, llvm or google.
	      Default is llvm.

   cppcoreguidelines-pro-bounds-pointer-arithmetic
       This check flags	all usage of pointer arithmetic, because it could lead
       to an invalid pointer. Subtraction of two pointers is  not  flagged  by
       this check.

       Pointers	should only refer to single objects, and pointer arithmetic is
       fragile and easy	to get wrong. span<T> is a bounds-checked,  safe  type
       for accessing arrays of data.

       This rule is part of the	"Bounds	safety"	profile	of the C++ Core	Guide-
       lines,								   see
       https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#Pro-bounds-arithmetic.

   cppcoreguidelines-pro-type-const-cast
       This check flags	all uses of const_cast in C++ code.

       Modifying a variable that was declared  const  is  undefined  behavior,
       even with const_cast.

       This  rule  is part of the "Type	safety"	profile	of the C++ Core	Guide-
       lines,								   see
       https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#Pro-type-constcast.

   cppcoreguidelines-pro-type-cstyle-cast
       This check flags	all use	of C-style casts that  perform	a  static_cast
       downcast, const_cast, or	reinterpret_cast.

       Use of these casts can violate type safety and cause the	program	to ac-
       cess a variable that is actually	of type	X to be	accessed as if it were
       of an unrelated type Z. Note that a C-style (T)expression cast means to
       perform the first of the	following that is possible:  a	const_cast,  a
       static_cast,  a	static_cast  followed  by  a  const_cast,  a  reinter-
       pret_cast, or a reinterpret_cast	followed by a  const_cast.  This  rule
       bans (T)expression only when used to perform an unsafe cast.

       This  rule  is part of the "Type	safety"	profile	of the C++ Core	Guide-
       lines,								   see
       https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#Pro-type-cstylecast.

   cppcoreguidelines-pro-type-member-init
       The check flags user-defined constructor	definitions that do  not  ini-
       tialize	all fields that	would be left in an undefined state by default
       construction,  e.g.  builtins,  pointers	 and  record   types   without
       user-provided  default  constructors containing at least	one such type.
       If these	fields aren't initialized, the constructor will	leave some  of
       the memory in an	undefined state.

       For  C++11  it  suggests	 fixes to add in-class field initializers. For
       older versions it inserts the field initializers	into  the  constructor
       initializer  list. It will also initialize any direct base classes that
       need to be zeroed in the	constructor initializer	list.

       The check takes assignment of fields in the constructor body  into  ac-
       count  but  generates false positives for fields	initialized in methods
       invoked in the constructor body.

       The check also flags variables with  automatic  storage	duration  that
       have  record types without a user-provided constructor and are not ini-
       tialized. The suggested fix is to zero initialize the variable  via  {}
       for C++11 and beyond or = {} for	older language versions.

   Options
       IgnoreArrays
	      If  set to non-zero, the check will not warn about array members
	      that are not zero-initialized during construction.  For  perfor-
	      mance  critical  code,  it  may  be  important to	not initialize
	      fixed-size array members.	Default	is 0.

       UseAssignment
	      If set to	non-zero, the check will provide fix-its with  literal
	      initializers  (  int i = 0; ) instead of curly braces ( int i{};
	      ).

       This rule is part of the	"Type safety" profile of the C++  Core	Guide-
       lines,	     corresponding	 to	  rule	     Type.6.	   See
       https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#Pro-type-memberinit.

   cppcoreguidelines-pro-type-reinterpret-cast
       This check flags	all uses of reinterpret_cast in	C++ code.

       Use of these casts can violate type safety and cause the	program	to ac-
       cess a variable that is actually	of type	X to be	accessed as if it were
       of an unrelated type Z.

       This  rule  is part of the "Type	safety"	profile	of the C++ Core	Guide-
       lines,								   see
       https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#Pro-type-reinterpretcast.

   cppcoreguidelines-pro-type-static-cast-downcast
       This check flags	all usages of  static_cast,  where  a  base  class  is
       casted to a derived class. In those cases, a fix-it is provided to con-
       vert the	cast to	a dynamic_cast.

       Use of these casts can violate type safety and cause the	program	to ac-
       cess a variable that is actually	of type	X to be	accessed as if it were
       of an unrelated type Z.

       This rule is part of the	"Type safety" profile of the C++  Core	Guide-
       lines,								   see
       https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#Pro-type-downcast.

   cppcoreguidelines-pro-type-union-access
       This  check  flags all access to	members	of unions. Passing unions as a
       whole is	not flagged.

       Reading from a union member assumes that	member was the last one	 writ-
       ten,  and  writing to a union member assumes another member with	a non-
       trivial destructor had its destructor called. This is  fragile  because
       it  cannot  generally be	enforced to be safe in the language and	so re-
       lies on programmer discipline to	get it right.

       This rule is part of the	"Type safety" profile of the C++  Core	Guide-
       lines,								   see
       https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#Pro-type-unions.

   cppcoreguidelines-pro-type-vararg
       This  check  flags all calls to c-style vararg functions	and all	use of
       va_arg.

       To allow	for SFINAE use of vararg functions, a call is not flagged if a
       literal 0 is passed as the only vararg argument.

       Passing to varargs assumes the correct type will	be read. This is frag-
       ile because it cannot generally be enforced to be safe in the  language
       and so relies on	programmer discipline to get it	right.

       This  rule  is part of the "Type	safety"	profile	of the C++ Core	Guide-
       lines,								   see
       https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#Pro-type-varargs.

   cppcoreguidelines-slicing
       Flags slicing of	member variables or vtable. Slicing happens when copy-
       ing a derived object into a base	object:	the members of the derived ob-
       ject (both member variables and virtual member functions) will be  dis-
       carded.	This can be misleading especially for member function slicing,
       for example:

	  struct B { int a; virtual int	f(); };
	  struct D : B { int b;	int f()	override; };

	  void use(B b)	{  // Missing reference, intended?
	    b.f();  // Calls B::f.
	  }

	  D d;
	  use(d);  // Slice.

       See  the	 relevant  C++	 Core	Guidelines   sections	for   details:
       https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#es63-dont-slice
       https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#c145-access-polymorphic-objects-through-pointers-and-references

   cppcoreguidelines-special-member-functions
       The  check  finds  classes where	some but not all of the	special	member
       functions are defined.

       By default the compiler defines a copy constructor, copy	assignment op-
       erator,	move constructor, move assignment operator and destructor. The
       default can be suppressed by explicit user-definitions.	The  relation-
       ship between which functions will be suppressed by definitions of other
       functions is complicated	and it is advised that all five	are  defaulted
       or explicitly defined.

       Note that defining a function with = delete is considered to be a defi-
       nition.

       This rule is part of the	"Constructors, assignments,  and  destructors"
       profile of the C++ Core Guidelines, corresponding to rule C.21. See

       https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#c21-if-you-define-or-delete-any-default-operation-define-or-delete-them-all.

   Options
       AllowSoleDefaultDtor
	      When set to 1 (default is	0), this check	doesn't	 flag  classes
	      with  a  sole,  explicitly  defaulted destructor.	An example for
	      such a class is:

		 struct	A {
		   virtual ~A()	= default;
		 };

       AllowMissingMoveFunctions
	      When set to 1 (default is	0), this check	doesn't	 flag  classes
	      which  define  no	move operations	at all.	It still flags classes
	      which define only	one of either move constructor or move assign-
	      ment  operator.  With  this  option enabled, the following class
	      won't be flagged:

		 struct	A {
		   A(const A&);
		   A& operator=(const A&);
		   ~A();
		 }

   fuchsia-default-arguments-calls
       Warns if	a function or method is	called with default arguments.

       For example, given the declaration:

	  int foo(int value = 5) { return value; }

       A function call expression that uses a default argument will  be	 diag-
       nosed.  Calling it without defaults will	not cause a warning:

	  foo();  // warning
	  foo(0); // no	warning

       See	the	 features      disallowed      in      Fuchsia	    at
       https://fuchsia.googlesource.com/zircon/+/master/docs/cxx.md

   fuchsia-default-arguments-declarations
       Warns if	a function or method is	declared with default parameters.

       For example, the	declaration:

	  int foo(int value = 5) { return value; }

       will cause a warning.

       See	the	 features      disallowed      in      Fuchsia	    at
       https://fuchsia.googlesource.com/zircon/+/master/docs/cxx.md

   fuchsia-header-anon-namespaces
       The  fuchsia-header-anon-namespaces  check  is  an  alias,  please  see
       google-build-namespace for more information.

   fuchsia-multiple-inheritance
       Warns if	a class	inherits from multiple classes that are	not pure  vir-
       tual.

       For  example,  declaring	 a  class that inherits	from multiple concrete
       classes is disallowed:

	  class	Base_A {
	  public:
	    virtual int	foo() {	return 0; }
	  };

	  class	Base_B {
	  public:
	    virtual int	bar() {	return 0; }
	  };

	  // Warning
	  class	Bad_Child1 : public Base_A, Base_B {};

       A class that inherits from a pure virtual is allowed:

	  class	Interface_A {
	  public:
	    virtual int	foo() =	0;
	  };

	  class	Interface_B {
	  public:
	    virtual int	bar() =	0;
	  };

	  // No	warning
	  class	Good_Child1 : public Interface_A, Interface_B {
	    virtual int	foo() override { return	0; }
	    virtual int	bar() override { return	0; }
	  };

       See	the	 features      disallowed      in      Fuchsia	    at
       https://fuchsia.googlesource.com/zircon/+/master/docs/cxx.md

   fuchsia-overloaded-operator
       Warns if	an operator is overloaded, except for the assignment (copy and
       move) operators.

       For example:

	  int operator+(int);	  // Warning

	  B &operator=(const B &Other);	 // No warning
	  B &operator=(B &&Other) // No	warning

       See	the	 features      disallowed      in      Fuchsia	    at
       https://fuchsia.googlesource.com/zircon/+/master/docs/cxx.md

   fuchsia-restrict-system-includes
       Checks for allowed system includes and suggests removal of any others.

       It  is  important  to note that running this check with fixes may break
       code, as	the fix	removes	headers.  Fixes	 are  applied  to  source  and
       header files, but not to	system headers.

       For example, given the allowed system includes 'a.h,b*':

	  #include <a.h>
	  #include <b.h>
	  #include <bar.h>
	  #include <c.h>    // Warning,	as c.h is not explicitly allowed

       All  system includes can	be allowed with	'*', and all can be disallowed
       with an empty string ('').

   Options
       Includes
	      A	string containing a comma separated glob list of  allowed  in-
	      clude  filenames.	  Similar to the -checks glob list for running
	      clang-tidy itself, the two wildcard characters are '*' and  '-',
	      to  include  and exclude globs, respectively.The default is '*',
	      which allows all includes.

   fuchsia-statically-constructed-objects
       Warns if	global,	non-trivial objects with static	storage	are  construc-
       ted,  unless the	object is statically initialized with a	constexpr con-
       structor	or has no explicit constructor.

       For example:

	  class	A {};

	  class	B {
	  public:
	    B(int Val) : Val(Val) {}
	  private:
	    int	Val;
	  };

	  class	C {
	  public:
	    C(int Val) : Val(Val) {}
	    constexpr C() : Val(0) {}

	  private:
	    int	Val;
	  };

	  static A a;	      // No warning, as	there is no explicit constructor
	  static C c(0);      // No warning, as	constructor is constexpr

	  static B b(0);      // Warning, as constructor is not	constexpr
	  static C c2(0, 1);  // Warning, as constructor is not	constexpr

	  static int i;	      // No warning, as	it is trivial

	  extern int get_i();
	  static C(get_i())   // Warning, as the constructor is	dynamically initialized

       See	the	 features      disallowed      in      Fuchsia	    at
       https://fuchsia.googlesource.com/zircon/+/master/docs/cxx.md

   fuchsia-trailing-return
       Functions  that	have trailing returns are disallowed, except for those
       using decltype specifiers and lambda with otherwise unutterable	return
       types.

       For example:

	  // No	warning
	  int add_one(const int	arg) { return arg; }

	  // Warning
	  auto get_add_one() ->	int (*)(const int) {
	    return add_one;
	  }

       Exceptions are made for lambdas and decltype specifiers:

	  // No	warning
	  auto lambda =	[](double x, double y) -> double {return x + y;};

	  // No	warning
	  template <typename T1, typename T2>
	  auto fn(const	T1 &lhs, const T2 &rhs)	-> decltype(lhs	+ rhs) {
	    return lhs + rhs;
	  }

       See	the	 features      disallowed      in      Fuchsia	    at
       https://fuchsia.googlesource.com/zircon/+/master/docs/cxx.md

   fuchsia-virtual-inheritance
       Warns if	classes	are defined with virtual inheritance.

       For example, classes should not be defined with virtual inheritance:

	  class	B : public virtual A {};   // warning

       See	the	 features      disallowed      in      Fuchsia	    at
       https://fuchsia.googlesource.com/zircon/+/master/docs/cxx.md

   google-build-explicit-make-pair
       Check that make_pair's template arguments are deduced.

       G++ 4.6 in C++11	mode fails badly if make_pair's	template arguments are
       specified explicitly, and such use isn't	intended in any	case.

       Corresponding cpplint.py	check name: build/explicit_make_pair.

   google-build-namespaces
       cert-dcl59-cpp redirects	here  as  an  alias  for  this	check.	 fuch-
       sia-header-anon-namespaces redirects here as an alias for this check.

       Finds anonymous namespaces in headers.

       https://google.github.io/styleguide/cppguide.html#Namespaces

       Corresponding cpplint.py	check name: build/namespaces.

   Options
       HeaderFileExtensions
	      A	 comma-separated  list	of filename extensions of header files
	      (the filename extensions should not include "." prefix). Default
	      is  "h,hh,hpp,hxx".   For	header files without an	extension, use
	      an empty string (if there	are no other  desired  extensions)  or
	      leave  an	empty element in the list. e.g., "h,hh,hpp,hxx," (note
	      the trailing comma).

   google-build-using-namespace
       Finds using namespace directives.

       The check implements the	following rule of the Google C++ Style Guide:
	  You may not use a using-directive to make all	names from a namespace
	  available.

	  // Forbidden -- This pollutes	the namespace.
	  using	namespace foo;

       Corresponding cpplint.py	check name: build/namespaces.

   google-default-arguments
       Checks that default arguments are not given for virtual methods.

       See https://google.github.io/styleguide/cppguide.html#Default_Arguments

   google-explicit-constructor
       Checks that constructors	callable with a	single argument	and conversion
       operators are marked explicit to	avoid the risk	of  unintentional  im-
       plicit conversions.

       Consider	this example:

	  struct S {
	    int	x;
	    operator bool() const { return true; }
	  };

	  bool f() {
	    S a{1};
	    S b{2};
	    return a ==	b;
	  }

       The  function  will  return true, since the objects are implicitly con-
       verted to bool before comparison, which is unlikely to be the intent.

       The check will suggest inserting	explicit  before  the  constructor  or
       conversion  operator  declaration.  However, copy and move constructors
       should not be explicit, as well as constructors taking  a  single  ini-
       tializer_list argument.

       This code:

	  struct S {
	    S(int a);
	    explicit S(const S&);
	    operator bool() const;
	    ...

       will become

	  struct S {
	    explicit S(int a);
	    S(const S&);
	    explicit operator bool() const;
	    ...

       See
       https://google.github.io/styleguide/cppguide.html#Explicit_Constructors

   google-global-names-in-headers
       Flag global namespace pollution in header  files.  Right	 now  it  only
       triggers	on using declarations and directives.

       The	   relevant	   style	guide	     section	    is
       https://google.github.io/styleguide/cppguide.html#Namespaces.

   Options
       HeaderFileExtensions
	      A	comma-separated	list of	filename extensions  of	 header	 files
	      (the filename extensions should not contain "." prefix). Default
	      is "h".  For header files	without	an  extension,	use  an	 empty
	      string  (if  there  are no other desired extensions) or leave an
	      empty element in	the  list.  e.g.,  "h,hh,hpp,hxx,"  (note  the
	      trailing comma).

   google-objc-avoid-nsobject-new
       Finds  calls  to	 +new  or overrides of it, which are prohibited	by the
       Google Objective-C style	guide.

       The Google Objective-C style guide forbids calling +new	or  overriding
       it in class implementations, preferring +alloc and -init	methods	to in-
       stantiate objects.

       An example:

	  NSDate *now =	[NSDate	new];
	  Foo *bar = [Foo new];

       Instead,	code should use	+alloc/-init or	class factory methods.

	  NSDate *now =	[NSDate	date];
	  Foo *bar = [[Foo alloc] init];

       This check corresponds to the Google Objective-C	Style  Guide  rule  Do
       Not Use +new.

   google-objc-avoid-throwing-exception
       Finds uses of throwing exceptions usages	in Objective-C files.

       For the same reason as the Google C++ style guide, we prefer not	throw-
       ing exceptions from Objective-C code.

       The	 corresponding	     C++       style	    guide	 rule:
       https://google.github.io/styleguide/cppguide.html#Exceptions

       Instead,	 prefer	passing	in NSError ** and return BOOL to indicate suc-
       cess or failure.

       A counterexample:

	  - (void)readFile {
	    if ([self isError])	{
	      @throw [NSException exceptionWithName:...];
	    }
	  }

       Instead,	returning an error via NSError ** is preferred:

	  - (BOOL)readFileWithError:(NSError **)error {
	    if ([self isError])	{
	      *error = [NSError	errorWithDomain:...];
	      return NO;
	    }
	    return YES;
	  }

       The	    corresponding	   style	  guide		 rule:
       https://google.github.io/styleguide/objcguide.html#avoid-throwing-exceptions

   google-objc-function-naming
       Finds function declarations in Objective-C files	that do	not follow the
       pattern described in the	Google Objective-C Style Guide.

       The    corresponding    style   guide   rule   can   be	 found	 here:
       https://google.github.io/styleguide/objcguide.html#function-names

       All function names should be in Pascal case.  Functions	whose  storage
       class is	not static should have an appropriate prefix.

       The following code sample does not follow this pattern:

	  static bool is_positive(int i) { return i > 0; }
	  bool IsNegative(int i) { return i < 0; }

       The sample above	might be corrected to the following code:

	  static bool IsPositive(int i)	{ return i > 0;	}
	  bool *ABCIsNegative(int i) { return i	< 0; }

   google-objc-global-variable-declaration
       Finds  global  variable	declarations  in Objective-C files that	do not
       follow the pattern of variable  names  in  Google's  Objective-C	 Style
       Guide.

       The	    corresponding	   style	  guide		 rule:
       https://google.github.io/styleguide/objcguide.html#variable-names

       All the global variables	should follow the pattern of  g[A-Z].*	(vari-
       ables)  or k[A-Z].* (constants).	The check will suggest a variable name
       that follows the	pattern	if it can be inferred from the original	name.

       For code:

	  static NSString* myString = @"hello";

       The fix will be:

	  static NSString* gMyString = @"hello";

       Another example of constant:

	  static NSString* const myConstString = @"hello";

       The fix will be:

	  static NSString* const kMyConstString	= @"hello";

       However for code	that prefixed with non-alphabetical characters like:

	  static NSString* __anotherString = @"world";

       The check will give a warning message but will not be able to suggest a
       fix. The	user need to fix it on his own.

   google-readability-avoid-underscore-in-googletest-name
       Checks  whether	there are underscores in googletest test and test case
       names in	test macros:

       o TEST

       o TEST_F

       o TEST_P

       o TYPED_TEST

       o TYPED_TEST_P

       The FRIEND_TEST macro is	not included.

       For example:

	  TEST(TestCaseName, Illegal_TestName) {}
	  TEST(Illegal_TestCaseName, TestName) {}

       would trigger the check.	Underscores are	not allowed in test names  nor
       test case names.

       The DISABLED_ prefix, which may be used to disable individual tests, is
       ignored when checking test names, but the rest of the rest of the  test
       name is still checked.

       This check does not propose any fixes.

   google-readability-braces-around-statements
       The  google-readability-braces-around-statements	 check	is  an	alias,
       please see readability-braces-around-statements for more	information.

   google-readability-casting
       Finds usages of C-style casts.

       https://google.github.io/styleguide/cppguide.html#Casting

       Corresponding cpplint.py	check name: readability/casting.

       This check is similar to	-Wold-style-cast, but  it  suggests  automated
       fixes  in  some	cases.	The reported locations should not be different
       from the	ones generated by -Wold-style-cast.

   google-readability-function-size
       The google-readability-function-size check  is  an  alias,  please  see
       readability-function-size for more information.

   google-readability-namespace-comments
       The google-readability-namespace-comments check is an alias, please see
       llvm-namespace-comment for more information.

   google-readability-todo
       Finds TODO comments without a username or bug number.

       The	  relevant	  style	       guide	    section	    is
       https://google.github.io/styleguide/cppguide.html#TODO_Comments.

       Corresponding cpplint.py	check: readability/todo

   google-runtime-int
       Finds uses of short, long and long long and suggest replacing them with
       u?intXX(_t)?.

       The	    corresponding	   style	  guide		 rule:
       https://google.github.io/styleguide/cppguide.html#Integer_Types.

       Correspondig cpplint.py check: runtime/int.

   Options
       UnsignedTypePrefix
	      A	string specifying the unsigned type prefix. Default is uint.

       SignedTypePrefix
	      A	string specifying the signed type prefix. Default is int.

       TypeSuffix
	      A	string specifying the type suffix. Default is an empty string.

   google-runtime-operator
       Finds overloads of unary	operator &.

       https://google.github.io/styleguide/cppguide.html#Operator_Overloading

       Corresponding cpplint.py	check name: runtime/operator.

   google-runtime-references
       Checks the usage	of non-constant	references in function parameters.

       The	    corresponding	   style	  guide		 rule:
       https://google.github.io/styleguide/cppguide.html#Reference_Arguments

   Options
       WhiteListTypes
	      A	semicolon-separated list of names of whitelist types.  Default
	      is empty.

   hicpp-avoid-c-arrays
       The    hicpp-avoid-c-arrays    check    is   an	 alias,	  please   see
       modernize-avoid-c-arrays	for more information.

   hicpp-avoid-goto
       The hicpp-avoid-goto check is an	alias to cppcoreguidelines-avoid-goto.
       Rule  6.3.1 High	Integrity C++ requires that goto only skips parts of a
       block and is not	used for other reasons.

       Both coding guidelines implement	the same exception  to	the  usage  of
       goto.

   hicpp-braces-around-statements
       The  hicpp-braces-around-statements  check  is  an  alias,  please  see
       readability-braces-around-statements for	more information.  It enforces
       the rule	6.1.1.

   hicpp-deprecated-headers
       The   hicpp-deprecated-headers	check	is   an	  alias,   please  see
       modernize-deprecated-headers for	more  information.   It	 enforces  the
       rule 1.3.3.

   hicpp-exception-baseclass
       Ensure  that  every  value that in a throw expression is	an instance of
       std::exception.

       This enforces rule 15.1 of the High Integrity C++ Coding	Standard.

	  class	custom_exception {};

	  void throwing() noexcept(false) {
	    // Problematic throw expressions.
	    throw int(42);
	    throw custom_exception();
	  }

	  class	mathematical_error : public std::exception {};

	  void throwing2() noexcept(false) {
	    // These kind of throws are	ok.
	    throw mathematical_error();
	    throw std::runtime_error();
	    throw std::exception();
	  }

   hicpp-explicit-conversions
       This check is an	alias for google-explicit-constructor.	 Used  to  en-
       force  parts  of	rule 5.4.1.  This check	will enforce that constructors
       and conversion operators	are marked explicit.  Other forms  of  casting
       checks  are  implemented	 in other places.  The following checks	can be
       used to check for more forms of casting:

       o cppcoreguidelines-pro-type-static-cast-downcast

       o cppcoreguidelines-pro-type-reinterpret-cast

       o cppcoreguidelines-pro-type-const-cast

       o cppcoreguidelines-pro-type-cstyle-cast

   hicpp-function-size
       This check is an	alias for readability-function-size.   Useful  to  en-
       force multiple sections on function complexity.

       o rule 8.2.2

       o rule 8.3.1

       o rule 8.3.2

   hicpp-invalid-access-moved
       This check is an	alias for bugprone-use-after-move.

       Implements  parts  of the rule 8.4.1 to check if	moved-from objects are
       accessed.

   hicpp-member-init
       This check is an	alias for cppcoreguidelines-pro-type-member-init.  Im-
       plements	 the  check for	rule 12.4.2 to initialize class	members	in the
       right order.

   hicpp-move-const-arg
       The   hicpp-move-const-arg   check   is	 an    alias,	 please	   see
       performance-move-const-arg  for more information.  It enforces the rule
       17.3.1.

   hicpp-multiway-paths-covered
       This check discovers situations where code paths	are not	fully-covered.
       It  furthermore suggests	using if instead of switch if the code will be
       more clear.  The	rule 6.1.2 and rule 6.1.4 of the  High	Integrity  C++
       Coding Standard are enforced.

       if-else	if  chains  that  miss a final else branch might lead to unex-
       pected program execution	and be the result of a logical error.  If  the
       missing	else branch is intended	you can	leave it empty with a clarify-
       ing comment.  This warning can be noisy on some code bases,  so	it  is
       disabled	by default.

	  void f1() {
	    int	i = determineTheNumber();

	     if(i > 0) {
	       // Some Calculation
	     } else if (i < 0) {
	       // Precondition violated	or something else.
	     }
	     //	...
	  }

       Similar	arguments  hold	 for  switch statements	which do not cover all
       possible	code paths.

	  // The missing default branch	might be a logical error. It can be kept empty
	  // if	there is nothing to do,	making it explicit.
	  void f2(int i) {
	    switch (i) {
	    case 0: // something
	      break;
	    case 1: // something else
	      break;
	    }
	    // All other numbers?
	  }

	  // Violates this rule	as well, but already emits a compiler warning (-Wswitch).
	  enum Color { Red, Green, Blue, Yellow	};
	  void f3(enum Color c)	{
	    switch (c) {
	    case Red: // We can't drive	for now.
	      break;
	    case Green:	 // We are allowed to drive.
	      break;
	    }
	    // Other cases missing
	  }

       The rule	6.1.4 requires every switch statement to  have	at  least  two
       case labels other than a	default	label.	Otherwise, the switch could be
       better expressed	with an	if statement.  Degenerated  switch  statements
       without any labels are caught as	well.

	  // Degenerated switch	that could be better written as	`if`
	  int i	= 42;
	  switch(i) {
	    case 1: // do something here
	    default: //	do somethe else	here
	  }

	  // Should rather be the following:
	  if (i	== 1) {
	    // do something here
	  }
	  else {
	    // do something here
	  }

	  // A completly degenerated switch will be diagnosed.
	  int i	= 42;
	  switch(i) {}

   Options
       WarnOnMissingElse
	      Boolean flag that	activates a warning for	missing	else branches.
	      Default is 0.

   hicpp-named-parameter
       This check is an	alias for readability-named-parameter.

       Implements rule 8.2.1.

   hicpp-new-delete-operators
       This check is an	alias for misc-new-delete-overloads.  Implements  rule
       12.3.1  to  ensure the new and delete operators have the	correct	signa-
       ture.

   hicpp-no-array-decay
       The   hicpp-no-array-decay   check   is	 an    alias,	 please	   see
       cppcoreguidelines-pro-bounds-array-to-pointer-decay  for	 more informa-
       tion.  It enforces the rule 4.1.1.

   hicpp-no-assembler
       Check for assembler statements. No fix is offered.

       Inline assembler	is forbidden by	the High Intergrity C++	 Coding	 Stan-
       dard as it restricts the	portability of code.

   hicpp-no-malloc
       The     hicpp-no-malloc	  check	   is	 an    alias,	 please	   see
       cppcoreguidelines-no-malloc for more information.  It enforces the rule
       5.3.2.

   hicpp-noexcept-move
       This  check is an alias for misc-noexcept-moveconstructor.  Checks rule
       12.5.4 to mark move assignment and move construction noexcept.

   hicpp-signed-bitwise
       Finds uses of bitwise operations	on signed  integer  types,  which  may
       lead to undefined or implementation defined behaviour.

       The  according rule is defined in the High Integrity C++	Standard, Sec-
       tion 5.6.1.

   hicpp-special-member-functions
       This check is an	alias for  cppcoreguidelines-special-member-functions.
       Checks  that  special  member functions have the	correct	signature, ac-
       cording to rule 12.5.7.

   hicpp-static-assert
       The   hicpp-static-assert   check   is	 an    alias,	 please	   see
       misc-static-assert for more information.	 It enforces the rule 7.1.10.

   hicpp-undelegated-constructor
       This check is an	alias for bugprone-undelegated-constructor.  Partially
       implements rule 12.4.5 to find misplaced	 constructor  calls  inside  a
       constructor.

	  struct Ctor {
	    Ctor();
	    Ctor(int);
	    Ctor(int, int);
	    Ctor(Ctor *i) {
	      // All Ctor() calls result in a temporary	object
	      Ctor(); // did you intend	to call	a delegated constructor?
	      Ctor(0); // did you intend to call a delegated constructor?
	      Ctor(1, 2); // did you intend to call a delegated	constructor?
	      foo();
	    }
	  };

   hicpp-uppercase-literal-suffix
       The  hicpp-uppercase-literal-suffix  check  is  an  alias,  please  see
       readability-uppercase-literal-suffix for	more information.

   hicpp-use-auto
       The hicpp-use-auto check	is an alias, please see	modernize-use-auto for
       more information.  It enforces the rule 7.1.8.

   hicpp-use-emplace
       The    hicpp-use-emplace	   check    is	  an	alias,	  please   see
       modernize-use-emplace for  more	information.   It  enforces  the  rule
       17.4.2.

   hicpp-use-equals-default
       This  check  is	an alias for modernize-use-equals-default.  Implements
       rule 12.5.1 to explicitly default special member	functions.

   hicpp-use-equals-delete
       This check is an	 alias	for  modernize-use-equals-delete.   Implements
       rule 12.5.1 to explicitly default or delete special member functions.

   hicpp-use-noexcept
       The    hicpp-use-noexcept    check    is	   an	 alias,	  please   see
       modernize-use-noexcept for more	information.   It  enforces  the  rule
       1.3.5.

   hicpp-use-nullptr
       The    hicpp-use-nullptr	   check    is	  an	alias,	  please   see
       modernize-use-nullptr for  more	information.   It  enforces  the  rule
       2.5.3.

   hicpp-use-override
       This  check  is	an  alias for modernize-use-override.  Implements rule
       10.2.1 to declare a virtual function override when overriding.

   hicpp-vararg
       The    hicpp-vararg    check    is     an     alias,	please	   see
       cppcoreguidelines-pro-type-vararg  for  more  information.  It enforces
       the rule	14.1.1.

   llvm-header-guard
       Finds and fixes header guards that do not adhere	to LLVM	style.

   Options
       HeaderFileExtensions
	      A	comma-separated	list of	filename extensions  of	 header	 files
	      (the filename extensions should not include "." prefix). Default
	      is "h,hh,hpp,hxx".  For header files without an  extension,  use
	      an  empty	 string	 (if there are no other	desired	extensions) or
	      leave an empty element in	the list. e.g.,	"h,hh,hpp,hxx,"	 (note
	      the trailing comma).

   llvm-include-order
       Checks the correct order	of #includes.

       See https://llvm.org/docs/CodingStandards.html#include-style

   llvm-namespace-comment
       google-readability-namespace-comments  redirects	 here  as an alias for
       this check.

       Checks that long	namespaces have	a closing comment.

       https://llvm.org/docs/CodingStandards.html#namespace-indentation

       https://google.github.io/styleguide/cppguide.html#Namespaces

	  namespace n1 {
	  void f();
	  }

	  // becomes

	  namespace n1 {
	  void f();
	  }  //	namespace n1

   Options
       ShortNamespaceLines
	      Requires the closing brace of the	 namespace  definition	to  be
	      followed	by  a closing comment if the body of the namespace has
	      more than	ShortNamespaceLines lines of code. The value is	an un-
	      signed integer that defaults to 1U.

       SpacesBeforeComments
	      An  unsigned  integer specifying the number of spaces before the
	      comment closing a	namespace definition. Default is 1U.

   llvm-prefer-isa-or-dyn-cast-in-conditionals
       Looks at	conditionals and finds and replaces  cases  of	cast<>,	 which
       will assert rather than return a	null pointer, and dyn_cast<> where the
       return value is not captured. Additionally, finds  and  replaces	 cases
       that  match  the	 pattern  var  &&  isa<X>(var),	where var is evaluated
       twice.

	  // Finds these:
	  if (auto x = cast<X>(y)) {}
	  // is	replaced by:
	  if (auto x = dyn_cast<X>(y)) {}

	  if (cast<X>(y)) {}
	  // is	replaced by:
	  if (isa<X>(y)) {}

	  if (dyn_cast<X>(y)) {}
	  // is	replaced by:
	  if (isa<X>(y)) {}

	  if (var && isa<T>(var)) {}
	  // is	replaced by:
	  if (isa_and_nonnull<T>(var.foo())) {}

	  // Other cases are ignored, e.g.:
	  if (auto f = cast<Z>(y)->foo()) {}
	  if (cast<Z>(y)->foo()) {}
	  if (X.cast(y)) {}

   llvm-twine-local
       Looks for local Twine variables which are prone to use after frees  and
       should be generally avoided.

	  static Twine Moo = Twine("bark") + "bah";

	  // becomes

	  static std::string Moo = (Twine("bark") + "bah").str();

   misc-definitions-in-headers
       Finds non-extern	non-inline function and	variable definitions in	header
       files, which can	lead to	potential ODR violations in case these headers
       are included from multiple translation units.

	  // Foo.h
	  int a	= 1; //	Warning: variable definition.
	  extern int d;	// OK: extern variable.

	  namespace N {
	    int	e = 2; // Warning: variable definition.
	  }

	  // Warning: variable definition.
	  const	char* str = "foo";

	  // OK: internal linkage variable definitions are ignored for now.
	  // Although these might also cause ODR violations, we	can be less certain and
	  // should try	to keep	the false-positive rate	down.
	  static int b = 1;
	  const	int c =	1;
	  const	char* const str2 = "foo";
	  constexpr int	k = 1;

	  // Warning: function definition.
	  int g() {
	    return 1;
	  }

	  // OK: inline	function definition is allowed to be defined multiple times.
	  inline int e() {
	    return 1;
	  }

	  class	A {
	  public:
	    int	f1() { return 1; } // OK: implicitly inline member function definition is allowed.
	    int	f2();

	    static int d;
	  };

	  // Warning: not an inline member function definition.
	  int A::f2() {	return 1; }

	  // OK: class static data member declaration is allowed.
	  int A::d = 1;

	  // OK: function template is allowed.
	  template<typename T>
	  T f3() {
	    T a	= 1;
	    return a;
	  }

	  // Warning: full specialization of a function	template is not	allowed.
	  template <>
	  int f3() {
	    int	a = 1;
	    return a;
	  }

	  template <typename T>
	  struct B {
	    void f1();
	  };

	  // OK: member	function definition of a class template	is allowed.
	  template <typename T>
	  void B<T>::f1() {}

	  class	CE {
	    constexpr static int i = 5;	// OK: inline variable definition.
	  };

	  inline int i = 5; // OK: inline variable definition.

	  constexpr int	f10() {	return 0; } // OK: constexpr function implies inline.

   Options
       HeaderFileExtensions
	      A	 comma-separated  list	of filename extensions of header files
	      (the filename extensions should not include "." prefix). Default
	      is  "h,hh,hpp,hxx".   For	header files without an	extension, use
	      an empty string (if there	are no other  desired  extensions)  or
	      leave  an	empty element in the list. e.g., "h,hh,hpp,hxx," (note
	      the trailing comma).

       UseHeaderFileExtension
	      When non-zero, the check will use	the file extension to  distin-
	      guish header files. Default is 1.

   misc-misplaced-const
       This  check diagnoses when a const qualifier is applied to a typedef to
       a pointer type rather than to the pointee, because such constructs  are
       often misleading	to developers because the const	applies	to the pointer
       rather than the pointee.

       For instance, in	the following code, the	resulting type is int *	 const
       rather than const int *:

	  typedef int *int_ptr;
	  void f(const int_ptr ptr);

       The  check  does	 not  diagnose	when  the underlying typedef type is a
       pointer to a const type or a function pointer type. This	is because the
       const  qualifier	 is less likely	to be mistaken because it would	be re-
       dundant (or disallowed) on the underlying pointee type.

   misc-new-delete-overloads
       cert-dcl54-cpp redirects	here as	an alias for this check.

       The check flags overloaded operator new() and operator  delete()	 func-
       tions  that  do	not  have  a corresponding free	store function defined
       within the same scope.  For instance, the check will flag a  class  im-
       plementation  of	a non-placement	operator new() when the	class does not
       also define a non-placement operator delete() function as well.

       The check does not flag implicitly-defined operators, deleted  or  pri-
       vate operators, or placement operators.

       This  check  corresponds	 to  CERT  C++ Coding Standard rule DCL54-CPP.
       Overload	allocation and deallocation functions as a pair	 in  the  same
       scope.

   misc-non-copyable-objects
       cert-fio38-c redirects here as an alias for this	check.

       The  check  flags  dereferences and non-pointer declarations of objects
       that are	not meant to be	passed by value, such as  C  FILE  objects  or
       POSIX pthread_mutex_t objects.

       This check corresponds to CERT C++ Coding Standard rule FIO38-C.	Do not
       copy a FILE object.

   misc-non-private-member-variables-in-classes
       cppcoreguidelines-non-private-member-variables-in-classes     redirects
       here as an alias	for this check.

       Finds  classes  that  contain  non-static  data	members	in addition to
       user-declared non-static	member functions and diagnose all data members
       declared	with a non-public access specifier. The	data members should be
       declared	as private and accessed	through	member	functions  instead  of
       exposed to derived classes or class consumers.

   Options
       IgnoreClassesWithAllMemberVariablesBeingPublic
	      Allows  to completely ignore classes if all the member variables
	      in that class a declared with a public access specifier.

       IgnorePublicMemberVariables
	      Allows to	ignore (not diagnose) all  the	member	variables  de-
	      clared with a public access specifier.

   misc-redundant-expression
       Detect	redundant  expressions	which  are  typically  errors  due  to
       copy-paste.

       Depending on the	operator expressions may be

       o redundant,

       o always	true,

       o always	false,

       o always	a constant (zero or one).

       Examples:

	  ((x+1) | (x+1))	      // (x+1) is redundant
	  (p->x	== p->x)	      // always	true
	  (p->x	< p->x)		      // always	false
	  (speed - speed + 1 ==	12)   // speed - speed is always zero

   misc-static-assert
       cert-dcl03-c redirects here as an alias for this	check.

       Replaces	assert() with static_assert() if the condition is  evaluatable
       at compile time.

       The  condition of static_assert() is evaluated at compile time which is
       safer and more efficient.

   misc-throw-by-value-catch-by-reference
       cert-err09-cpp  redirects  here	 as   an   alias   for	 this	check.
       cert-err61-cpp redirects	here as	an alias for this check.

       Finds  violations of the	rule "Throw by value, catch by reference" pre-
       sented for example in "C++  Coding  Standards"  by  H.  Sutter  and  A.
       Alexandrescu,  as  well as the CERT C++ Coding Standard rule ERR61-CPP.
       Catch exceptions	by lvalue reference.

       Exceptions:

	      o	Throwing string	literals will not be flagged despite  being  a
		pointer.  They are not susceptible to slicing and the usage of
		string literals	is idomatic.

	      o	Catching character pointers (char, wchar_t, unicode  character
		types) will not	be flagged to allow catching sting literals.

	      o	Moved  named  values  will  not	 be flagged as not throwing an
		anonymous temporary. In	this case we can be sure that the user
		knows  that  the object	can't be accessed outside catch	blocks
		handling the error.

	      o	Throwing function parameters will not be flagged as not	throw-
		ing  an	 anonymous temporary. This allows helper functions for
		throwing.

	      o	Re-throwing caught exception variables will not	be flragged as
		not throwing an	anonymous temporary. Although this can usually
		be done	by just	writing	throw; it happens often	enough in real
		code.

   Options
       CheckThrowTemporaries
	      Triggers	detection  of  violations  of  the CERT	recommendation
	      ERR09-CPP. Throw anonymous temporaries.  Default is 1.

       WarnOnLargeObject
	      Also warns for any large,	trivial	object caught by value.	Catch-
	      ing  a  large  object  by	value is not dangerous but affects the
	      performance negatively. The maximum size of an object allowed to
	      be  caught  without warning can be set using the MaxSize option.
	      Default is 0.

       MaxSize
	      Determines the maximum size of an	object allowed	to  be	caught
	      without  warning.	Only applicable	if WarnOnLargeObject is	set to
	      1.  If  option  is  set  by  the	 user	to   std::numeric_lim-
	      its_uint64_t_::max()  then it reverts to the default value.  De-
	      fault is the size	of size_t.

   misc-unconventional-assign-operator
       Finds declarations of assign operators with the wrong return and/or ar-
       gument  types  and  definitions	with good return type but wrong	return
       statements.

	  o The	return type must be Class&.

	  o Works with move-assign and assign by value.

	  o Private and	deleted	operators are ignored.

	  o The	operator must always return *this.

   misc-uniqueptr-reset-release
       Find and	replace	unique_ptr::reset(release()) with std::move().

       Example:

	  std::unique_ptr<Foo> x, y;
	  x.reset(y.release());	-> x = std::move(y);

       If y is already rvalue, std::move() is not added. x and y can  also  be
       std::unique_ptr<Foo>*.

   misc-unused-alias-decls
       Finds unused namespace alias declarations.

   misc-unused-parameters
       Finds  unused  function parameters. Unused parameters may signify a bug
       in the code (e.g. when a	different parameter is used instead). The sug-
       gested  fixes either comment parameter name out or remove the parameter
       completely, if all callers of the function are in the same  translation
       unit and	can be updated.

       The  check is similar to	the -Wunused-parameter compiler	diagnostic and
       can be used to prepare a	codebase to enabling of	 that  diagnostic.  By
       default the check is more permissive (see StrictMode).

	  void a(int i)	{ /*some code that doesn't use `i`*/ }

	  // becomes

	  void a(int  /*i*/) { /*some code that	doesn't	use `i`*/ }

	  static void staticFunctionA(int i);
	  static void staticFunctionA(int i) { /*some code that	doesn't	use `i`*/ }

	  // becomes

	  static void staticFunctionA()
	  static void staticFunctionA()	{ /*some code that doesn't use `i`*/ }

   Options
       StrictMode
	      When  zero  (default value), the check will ignore trivially un-
	      used parameters, i.e. when the  corresponding  function  has  an
	      empty  body  (and	 in case of constructors - no constructor ini-
	      tializers). When the function body is empty, an unused parameter
	      is unlikely to be	unnoticed by a human reader, and there's basi-
	      cally no place for a bug to hide.

   misc-unused-using-decls
       Finds unused using declarations.

       Example:

	  namespace n {	class C; }
	  using	n::C;  // Never	actually used.

   modernize-avoid-bind
       The check finds uses of std::bind and replaces simple uses  with	 lamb-
       das.  Lambdas will use value-capture where required.

       Right now it only handles free functions, not member functions.

       Given:

	  int add(int x, int y)	{ return x + y;	}

       Then:

	  void f() {
	    int	x = 2;
	    auto clj = std::bind(add, x, _1);
	  }

       is replaced by:

	  void f() {
	    int	x = 2;
	    auto clj = [=](auto	&& arg1) { return add(x, arg1);	};
	  }

       std::bind can be	hard to	read and can result in larger object files and
       binaries	due to type information	that will not be produced  by  equiva-
       lent lambdas.

   modernize-avoid-c-arrays
       cppcoreguidelines-avoid-c-arrays	 redirects  here  as an	alias for this
       check.

       hicpp-avoid-c-arrays redirects here as an alias for this	check.

       Finds C-style array types and recommend to use std::array<> / std::vec-
       tor<>. All types	of C arrays are	diagnosed.

       However,	 fix-it	 are  potentially  dangerous  in  header files and are
       therefore not emitted right now.

	  int a[] = {1,	2}; // warning:	do not declare C-style arrays, use std::array<>	instead

	  int b[1]; // warning:	do not declare C-style arrays, use std::array<>	instead

	  void foo() {
	    int	c[b[0]]; // warning: do	not declare C VLA arrays, use std::vector<> instead
	  }

	  template <typename T,	int Size>
	  class	array {
	    T d[Size]; // warning: do not declare C-style arrays, use std::array<> instead

	    int	e[1]; // warning: do not declare C-style arrays, use std::array<> instead
	  };

	  array<int[4],	2> d; // warning: do not declare C-style arrays, use std::array<> instead

	  using	k = int[4]; // warning:	do not declare C-style arrays, use std::array<>	instead

       However,	the extern "C" code is ignored,	since it is  common  to	 share
       such headers between C code, and	C++ code.

	  // Some header
	  extern "C" {

	  int f[] = {1,	2}; // not diagnosed

	  int j[1]; // not diagnosed

	  inline void bar() {
	    {
	      int j[j[0]]; // not diagnosed
	    }
	  }

	  }

       Similarly, the main() function is ignored. Its second and third parame-
       ters can	be either char*	argv[] or char** argv, but can not be std::ar-
       ray<>.

   modernize-concat-nested-namespaces
       Checks for use of nested	namespaces such	as namespace a { namespace b {
       ... } } and suggests changing to	the more concise syntax	introduced  in
       C++17: namespace	a::b { ... }.  Inline namespaces are not modified.

       For example:

	  namespace n1 {
	  namespace n2 {
	  void t();
	  }
	  }

	  namespace n3 {
	  namespace n4 {
	  namespace n5 {
	  void t();
	  }
	  }
	  namespace n6 {
	  namespace n7 {
	  void t();
	  }
	  }
	  }

       Will be modified	to:

	  namespace n1::n2 {
	  void t();
	  }

	  namespace n3 {
	  namespace n4::n5 {
	  void t();
	  }
	  namespace n6::n7 {
	  void t();
	  }
	  }

   modernize-deprecated-headers
       Some  headers  from  C library were deprecated in C++ and are no	longer
       welcome in C++ codebases. Some have no effect in	C++. For more  details
       refer to	the C++	14 Standard [depr.c.headers] section.

       This  check replaces C standard library headers with their C++ alterna-
       tives and removes redundant ones.

       Improtant note: the Standard doesn't guarantee that the C++ headers de-
       clare  all the same functions in	the global namespace. The check	in its
       current form can	break the code that  uses  library  symbols  from  the
       global namespace.

       o _assert.h_

       o _complex.h_

       o _ctype.h_

       o _errno.h_

       o _fenv.h_     // deprecated since C++11

       o _float.h_

       o _inttypes.h_

       o _limits.h_

       o _locale.h_

       o _math.h_

       o _setjmp.h_

       o _signal.h_

       o _stdarg.h_

       o _stddef.h_

       o _stdint.h_

       o _stdio.h_

       o _stdlib.h_

       o _string.h_

       o _tgmath.h_   // deprecated since C++11

       o _time.h_

       o _uchar.h_    // deprecated since C++11

       o _wchar.h_

       o _wctype.h_

       If  the	specified standard is older than C++11 the check will only re-
       place headers deprecated	before C++11, otherwise	-- every  header  that
       appeared	in the previous	list.

       These headers don't have	effect in C++:

       o _iso646.h_

       o _stdalign.h_

       o _stdbool.h_

   modernize-deprecated-ios-base-aliases
       Detects	usage  of the deprecated member	types of std::ios_base and re-
       places those that have a	non-deprecated equivalent.

		+-------------------------+-------------------------+
		|Deprecated member type	  | Replacement		    |
		+-------------------------+-------------------------+
		|std::ios_base::io_state  | std::ios_base::iostate  |
		+-------------------------+-------------------------+
		|std::ios_base::open_mode | std::ios_base::openmode |
		+-------------------------+-------------------------+
		|std::ios_base::seek_dir  | std::ios_base::seekdir  |
		+-------------------------+-------------------------+
		|std::ios_base::streamoff |			    |
		+-------------------------+-------------------------+
		|std::ios_base::streampos |			    |
		+-------------------------+-------------------------+

   modernize-loop-convert
       This check converts for(...; ...; ...) loops to use the new range-based
       loops in	C++11.

       Three kinds of loops can	be converted:

       o Loops over statically allocated arrays.

       o Loops over containers,	using iterators.

       o Loops over array-like containers, using operator[] and	at().

   MinConfidence option
   risky
       In  loops  where	 the  container	expression is more complex than	just a
       reference to a declared expression (a variable, function, enum,	etc.),
       and  some part of it appears elsewhere in the loop, we lower our	confi-
       dence in	the transformation due to the increased	risk of	 changing  se-
       mantics.	 Transformations for these loops are marked as risky, and thus
       will only be converted if the minimum required confidence level is  set
       to risky.

	  int arr[10][20];
	  int l	= 5;

	  for (int j = 0; j < 20; ++j)
	    int	k = arr[l][j] +	l; // using l outside arr[l] is	considered risky

	  for (int i = 0; i < obj.getVector().size(); ++i)
	    obj.foo(10); // using 'obj'	is considered risky

       See Range-based loops evaluate end() only once for an example of	an in-
       correct transformation when the minimum required	 confidence  level  is
       set to risky.

   reasonable (Default)
       If a loop calls .end() or .size() after each iteration, the transforma-
       tion for	that loop is marked as reasonable, and thus will be  converted
       if  the	required  confidence  level  is	set to reasonable (default) or
       lower.

	  // using size() is considered	reasonable
	  for (int i = 0; i < container.size();	++i)
	    cout << container[i];

   safe
       Any other loops that do not match the above criteria to	be  marked  as
       risky  or reasonable are	marked safe, and thus will be converted	if the
       required	confidence level is set	to safe	or lower.

	  int arr[] = {1,2,3};

	  for (int i = 0; i < 3; ++i)
	    cout << arr[i];

   Example
       Original:

	  const	int N =	5;
	  int arr[] = {1,2,3,4,5};
	  vector<int> v;
	  v.push_back(1);
	  v.push_back(2);
	  v.push_back(3);

	  // safe conversion
	  for (int i = 0; i < N; ++i)
	    cout << arr[i];

	  // reasonable	conversion
	  for (vector<int>::iterator it	= v.begin(); it	!= v.end(); ++it)
	    cout << *it;

	  // reasonable	conversion
	  for (int i = 0; i < v.size();	++i)
	    cout << v[i];

       After applying the check	with minimum confidence	level set  to  reason-
       able (default):

	  const	int N =	5;
	  int arr[] = {1,2,3,4,5};
	  vector<int> v;
	  v.push_back(1);
	  v.push_back(2);
	  v.push_back(3);

	  // safe conversion
	  for (auto & elem : arr)
	    cout << elem;

	  // reasonable	conversion
	  for (auto & elem : v)
	    cout << elem;

	  // reasonable	conversion
	  for (auto & elem : v)
	    cout << elem;

   Limitations
       There  are  certain  situations	where the tool may erroneously perform
       transformations that remove information and change semantics. Users  of
       the  tool should	be aware of the	behaviour and limitations of the check
       outlined	by the cases below.

   Comments inside loop	headers
       Comments	inside the original loop header	are ignored and	 deleted  when
       transformed.

	  for (int i = 0; i < N; /* This will be deleted */ ++i) { }

   Range-based loops evaluate end() only once
       The  C++11  range-based for loop	calls .end() only once during the ini-
       tialization of the loop.	If in the original loop	.end() is called after
       each iteration the semantics of the transformed loop may	differ.

	  // The following is semantically equivalent to the C++11 range-based for loop,
	  // therefore the semantics of	the header will	not change.
	  for (iterator	it = container.begin(),	e = container.end(); it	!= e; ++it) { }

	  // Instead of	calling	.end() after each iteration, this loop will be
	  // transformed to call .end()	only once during the initialization of the loop,
	  // which may affect semantics.
	  for (iterator	it = container.begin();	it != container.end(); ++it) { }

       As  explained  above,  calling member functions of the container	in the
       body of the loop	is considered risky. If	 the  called  member  function
       modifies	 the container the semantics of	the converted loop will	differ
       due to .end() being called only once.

	  bool flag = false;
	  for (vector<T>::iterator it =	vec.begin(); it	!= vec.end(); ++it) {
	    // Add a copy of the first element to the end of the vector.
	    if (!flag) {
	      // This line makes this transformation 'risky'.
	      vec.push_back(*it);
	      flag = true;
	    }
	    cout << *it;
	  }

       The original code above prints out the contents of  the	container  in-
       cluding	the newly added	element	while the converted loop, shown	below,
       will only print the original contents and not the newly added element.

	  bool flag = false;
	  for (auto & elem : vec) {
	    // Add a copy of the first element to the end of the vector.
	    if (!flag) {
	      // This line makes this transformation 'risky'
	      vec.push_back(elem);
	      flag = true;
	    }
	    cout << elem;
	  }

       Semantics will also be affected if .end() has side effects.  For	 exam-
       ple,  in	 the  case where calls to .end() are logged the	semantics will
       change in the transformed loop if .end()	was  originally	 called	 after
       each iteration.

	  iterator end() {
	    num_of_end_calls++;
	    return container.end();
	  }

   Overloaded operator->() with	side effects
       Similarly, if operator->() was overloaded to have side effects, such as
       logging,	the semantics will change. If the iterator's operator->()  was
       used  in	 the  original	loop  it will be replaced with <container ele-
       ment>.<member> instead due to the implicit dereference as part  of  the
       range-based  for	loop.  Therefore any side effect of the	overloaded op-
       erator->() will no longer be performed.

	  for (iterator	it = c.begin();	it != c.end(); ++it) {
	    it->func();	// Using operator->()
	  }
	  // Will be transformed to:
	  for (auto & elem : c)	{
	    elem.func(); // No longer using operator->()
	  }

   Pointers and	references to containers
       While most of the check's risk analysis	is  dedicated  to  determining
       whether	the  iterator or container was modified	within the loop, it is
       possible	to circumvent the analysis by accessing	and modifying the con-
       tainer through a	pointer	or reference.

       If  the	container  were	 directly used instead of using	the pointer or
       reference the following transformation would have only been applied  at
       the  risky  level  since	 calling a member function of the container is
       considered risky.  The check  cannot  identify  expressions  associated
       with  the  container  that  are different than the one used in the loop
       header, therefore the transformation below ends up being	 performed  at
       the safe	level.

	  vector<int> vec;

	  vector<int> *ptr = &vec;
	  vector<int> &ref = vec;

	  for (vector<int>::iterator it	= vec.begin(), e = vec.end(); it != e; ++it) {
	    if (!flag) {
	      // Accessing and modifying the container is considered risky, but	the risk
	      // level is not raised here.
	      ptr->push_back(*it);
	      ref.push_back(*it);
	      flag = true;
	    }
	  }

   OpenMP
       As  range-based for loops are only available since OpenMP 5, this check
       should not been used on	code  with  a  compatibility  requirements  of
       OpenMP  prior  to version 5. It is intentional that this	check does not
       make any	attempts to exclude incorrect diagnostics on OpenMP for	 loops
       prior to	OpenMP 5.

       To prevent this check to	be applied (and	to break) OpenMP for loops but
       still be	applied	to non-OpenMP for  loops  the  usage  of  NOLINT  (see
       clang-tidy-nolint) on the specific for loops is recommended.

   modernize-make-shared
       This  check finds the creation of std::shared_ptr objects by explicitly
       calling the constructor and a new expression, and replaces  it  with  a
       call to std::make_shared.

	  auto my_ptr =	std::shared_ptr<MyPair>(new MyPair(1, 2));

	  // becomes

	  auto my_ptr =	std::make_shared<MyPair>(1, 2);

       This  check also	finds calls to std::shared_ptr::reset()	with a new ex-
       pression, and replaces it with a	call to	std::make_shared.

	  my_ptr.reset(new MyPair(1, 2));

	  // becomes

	  my_ptr = std::make_shared<MyPair>(1, 2);

   Options
       MakeSmartPtrFunction
	      A	string specifying the name of  make-shared-ptr	function.  De-
	      fault is std::make_shared.

       MakeSmartPtrFunctionHeader
	      A	 string	specifying the corresponding header of make-shared-ptr
	      function.	 Default is memory.

       IncludeStyle
	      A	string specifying which	include-style is used, llvm or google.
	      Default is llvm.

       IgnoreMacros
	      If  set  to  non-zero,  the  check will not give warnings	inside
	      macros. Default is 1.

   modernize-make-unique
       This check finds	the creation of	std::unique_ptr	objects	by  explicitly
       calling	the  constructor  and a	new expression,	and replaces it	with a
       call to std::make_unique, introduced in C++14.

	  auto my_ptr =	std::unique_ptr<MyPair>(new MyPair(1, 2));

	  // becomes

	  auto my_ptr =	std::make_unique<MyPair>(1, 2);

       This check also finds calls to std::unique_ptr::reset() with a new  ex-
       pression, and replaces it with a	call to	std::make_unique.

	  my_ptr.reset(new MyPair(1, 2));

	  // becomes

	  my_ptr = std::make_unique<MyPair>(1, 2);

   Options
       MakeSmartPtrFunction
	      A	 string	 specifying  the name of make-unique-ptr function. De-
	      fault is std::make_unique.

       MakeSmartPtrFunctionHeader
	      A	string specifying the corresponding header of  make-unique-ptr
	      function.	 Default is memory.

       IncludeStyle
	      A	string specifying which	include-style is used, llvm or google.
	      Default is llvm.

       IgnoreMacros
	      If set to	non-zero, the check  will  not	give  warnings	inside
	      macros. Default is 1.

   modernize-pass-by-value
       With  move semantics added to the language and the standard library up-
       dated with move constructors added for many types it is now interesting
       to  take	 an argument directly by value,	instead	of by const-reference,
       and then	copy. This check allows	the compiler to	take care of  choosing
       the best	way to construct the copy.

       The  transformation  is usually beneficial when the calling code	passes
       an rvalue and assumes the move construction is a	cheap operation.  This
       short example illustrates how the construction of the value happens:

	  void foo(std::string s);
	  std::string get_str();

	  void f(const std::string &str) {
	    foo(str);	    // lvalue  -> copy construction
	    foo(get_str()); // prvalue -> move construction
	  }

       NOTE:
	  Currently,   only  constructors  are	transformed  to	 make  use  of
	  pass-by-value.  Contributions	that handle other situations are  wel-
	  come!

   Pass-by-value in constructors
       Replaces	 the  uses of const-references constructor parameters that are
       copied into class fields. The parameter is then moved with std::move().

       Since std::move() is a library function declared	in _utility_ it	may be
       necessary to add	this include. The check	will add the include directive
       when necessary.

	   #include <string>

	   class Foo {
	   public:
	  -  Foo(const std::string &Copied, const std::string &ReadOnly)
	  -    : Copied(Copied), ReadOnly(ReadOnly)
	  +  Foo(std::string Copied, const std::string &ReadOnly)
	  +    : Copied(std::move(Copied)), ReadOnly(ReadOnly)
	     {}

	   private:
	     std::string Copied;
	     const std::string &ReadOnly;
	   };

	   std::string get_cwd();

	   void	f(const	std::string &Path) {
	     //	The parameter corresponding to 'get_cwd()' is move-constructed.	By
	     //	using pass-by-value in the Foo constructor we managed to avoid a
	     //	copy-construction.
	     Foo foo(get_cwd(),	Path);
	   }

       If the parameter	is used	more than once no transformation is  performed
       since  moved  objects  have  an undefined state.	It means the following
       code will be left untouched:

	  #include <string>

	  void pass(const std::string &S);

	  struct Foo {
	    Foo(const std::string &S) :	Str(S) {
	      pass(S);
	    }

	    std::string	Str;
	  };

   Known limitations
       A situation where the generated code can	be wrong is  when  the	object
       referenced is modified before the assignment in the init-list through a
       "hidden"	reference.

       Example:

	   std::string s("foo");

	   struct Base {
	     Base() {
	       s = "bar";
	     }
	   };

	   struct Derived : Base {
	  -  Derived(const std::string &S) : Field(S)
	  +  Derived(std::string S) : Field(std::move(S))
	     { }

	     std::string Field;
	   };

	   void	f() {
	  -  Derived d(s); // d.Field holds "bar"
	  +  Derived d(s); // d.Field holds "foo"
	   }

   Note	about delayed template parsing
       When delayed template parsing is	enabled,  constructors	part  of  tem-
       plated  contexts;  templated  constructors,  constructors in class tem-
       plates, constructors of inner classes of	template  classes,  etc.,  are
       not transformed.	Delayed	template parsing is enabled by default on Win-
       dows as a Microsoft extension: Clang Compiler User_as Manual - Microsoft
       extensions.

       Delayed	template  parsing  can	be  enabled  using  the	-fdelayed-tem-
       plate-parsing flag and disabled using -fno-delayed-template-parsing.

       Example:

	    template <typename T> class	C {
	      std::string S;

	    public:
	  =  //	using -fdelayed-template-parsing (default on Windows)
	  =  C(const std::string &S) : S(S) {}

	  +  //	using -fno-delayed-template-parsing (default on	non-Windows systems)
	  +  C(std::string S) :	S(std::move(S))	{}
	    };

       SEE ALSO:
	  For more information	about  the  pass-by-value  idiom,  read:  Want
	  Speed? Pass by Value.

   Options
       IncludeStyle
	      A	string specifying which	include-style is used, llvm or google.
	      Default is llvm.

       ValuesOnly
	      When non-zero, the check only warns about	copied parameters that
	      are already passed by value. Default is 0.

   modernize-raw-string-literal
       This  check  selectively	 replaces  string  literals containing escaped
       characters with raw string literals.

       Example:

	  const	char *const Quotes{"embedded \"quotes\""};
	  const	char *const Paragraph{"Line one.\nLine two.\nLine three.\n"};
	  const	char *const SingleLine{"Single line.\n"};
	  const	char *const TrailingSpace{"Look	here ->	\n"};
	  const	char *const Tab{"One\tTwo\n"};
	  const	char *const Bell{"Hello!\a  And	welcome!"};
	  const	char *const Path{"C:\\Program Files\\Vendor\\Application.exe"};
	  const	char *const RegEx{"\\w\\([a-z]\\)"};

       becomes

	  const	char *const Quotes{R"(embedded "quotes")"};
	  const	char *const Paragraph{"Line one.\nLine two.\nLine three.\n"};
	  const	char *const SingleLine{"Single line.\n"};
	  const	char *const TrailingSpace{"Look	here ->	\n"};
	  const	char *const Tab{"One\tTwo\n"};
	  const	char *const Bell{"Hello!\a  And	welcome!"};
	  const	char *const Path{R"(C:\Program Files\Vendor\Application.exe)"};
	  const	char *const RegEx{R"(\w\([a-z]\))"};

       The presence of any of the following escapes can	cause the string to be
       converted  to  a	raw string literal: \\,	\', \",	\?, and	octal or hexa-
       decimal escapes for printable ASCII characters.

       A string	literal	containing only	escaped	newlines is a  common  way  of
       writing	lines  of  text	output.	Introducing physical newlines with raw
       string literals in this case is likely  to  impede  readability.	 These
       string literals are left	unchanged.

       An  escaped  horizontal	tab,  form  feed, or vertical tab prevents the
       string literal from being converted. The	presence of a horizontal  tab,
       form feed or vertical tab in source code	is not visually	obvious.

   modernize-redundant-void-arg
       Find and	remove redundant void argument lists.

       Examples:

		   +---------------------------+-------------------------+
		   |Initial code	       | Code with applied fixes |
		   +---------------------------+-------------------------+
		   |int	f(void);	       | int f();		 |
		   +---------------------------+-------------------------+
		   |int	(*f(void))(void);      | int (*f())();		 |
		   +---------------------------+-------------------------+
		   |typedef		   int | typedef int (*f_t())(); |
		   |(*f_t(void))(void);	       |			 |
		   +---------------------------+-------------------------+
		   |void (C::*p)(void);	       | void (C::*p)();	 |
		   +---------------------------+-------------------------+
		   |C::C(void) {}	       | C::C()	{}		 |
		   +---------------------------+-------------------------+
		   |C::~C(void)	{}	       | C::~C() {}		 |
		   +---------------------------+-------------------------+

   modernize-replace-auto-ptr
       This check replaces the uses of the deprecated class  std::auto_ptr  by
       std::unique_ptr	(introduced in C++11). The transfer of ownership, done
       by the copy-constructor and the	assignment  operator,  is  changed  to
       match std::unique_ptr usage by using explicit calls to std::move().

       Migration example:

	  -void	take_ownership_fn(std::auto_ptr<int> int_ptr);
	  +void	take_ownership_fn(std::unique_ptr<int> int_ptr);

	   void	f(int x) {
	  -  std::auto_ptr<int>	a(new int(x));
	  -  std::auto_ptr<int>	b;
	  +  std::unique_ptr<int> a(new	int(x));
	  +  std::unique_ptr<int> b;

	  -  b = a;
	  -  take_ownership_fn(b);
	  +  b = std::move(a);
	  +  take_ownership_fn(std::move(b));
	   }

       Since std::move() is a library function declared	in <utility> it	may be
       necessary to add	this include. The check	will add the include directive
       when necessary.

   Known Limitations
       o If  headers  modification  is not activated or	if a header is not al-
	 lowed to be changed this check	will produce broken code  (compilation
	 error),  where	 the  headers' code will stay unchanged	while the code
	 using them will be changed.

       o Client	code that declares a reference to an std::auto_ptr coming from
	 code that can't be migrated (such as a	header coming from a 3rd party
	 library) will produce a compilation error after  migration.  This  is
	 because  the type of the reference will be changed to std::unique_ptr
	 but the type returned by the library won't change, binding  a	refer-
	 ence  to  std::unique_ptr from	an std::auto_ptr. This pattern doesn't
	 make much sense and usually std::auto_ptr are stored by value (other-
	 wise  what  is	 the  point  in	using them instead of a	reference or a
	 pointer?).

	   // <3rd-party header...>
	   std::auto_ptr<int> get_value();
	   const std::auto_ptr<int> & get_ref();

	   // <calling code (with migration)...>
	  -std::auto_ptr<int> a(get_value());
	  +std::unique_ptr<int>	a(get_value());	// ok, unique_ptr constructed from auto_ptr

	  -const std::auto_ptr<int> & p	= get_ptr();
	  +const std::unique_ptr<int> &	p = get_ptr(); // won't	compile

       o Non-instantiated templates aren't modified.

	  template <typename X>
	  void f() {
	      std::auto_ptr<X> p;
	  }

	  // only 'f<int>()' (or similar) will trigger the replacement.

   Options
       IncludeStyle
	      A	string specifying which	include-style is used, llvm or google.
	      Default is llvm.

   modernize-replace-random-shuffle
       This  check will	find occurrences of std::random_shuffle	and replace it
       with std::shuffle. In  C++17  std::random_shuffle  will	no  longer  be
       available and thus we need to replace it.

       Below  are  two	examples of what kind of occurrences will be found and
       two examples of what it will be replaced	with.

	  std::vector<int> v;

	  // First example
	  std::random_shuffle(vec.begin(), vec.end());

	  // Second example
	  std::random_shuffle(vec.begin(), vec.end(), randomFunc);

       Both of these examples will be replaced with:

	  std::shuffle(vec.begin(), vec.end(), std::mt19937(std::random_device()()));

       The second example will also receive a warning that  randomFunc	is  no
       longer  supported  in  the  same	way as before so if the	user wants the
       same functionality, the user will need to change	the implementation  of
       the randomFunc.

       One  thing  to be aware of here is that std::random_device is quite ex-
       pensive to initialize. So if you	are using the code  in	a  performance
       critical	 place,	you probably want to initialize	it elsewhere.  Another
       thing is	that the seeding quality of the	suggested fix is  quite	 poor:
       std::mt19937  has an internal state of 624 32-bit integers, but is only
       seeded with a single integer. So	if you require higher quality  random-
       ness, you should	consider seeding better, for example:

	  std::shuffle(v.begin(), v.end(), []()	{
	    std::mt19937::result_type seeds[std::mt19937::state_size];
	    std::random_device device;
	    std::uniform_int_distribution<typename std::mt19937::result_type> dist;
	    std::generate(std::begin(seeds), std::end(seeds), [&] { return dist(device); });
	    std::seed_seq seq(std::begin(seeds), std::end(seeds));
	    return std::mt19937(seq);
	  }());

   modernize-return-braced-init-list
       Replaces	 explicit  calls  to the constructor in	a return with a	braced
       initializer list. This way the return type is not needlessly duplicated
       in the function definition and the return statement.

	  Foo bar() {
	    Baz	baz;
	    return Foo(baz);
	  }

	  // transforms	to:

	  Foo bar() {
	    Baz	baz;
	    return {baz};
	  }

   modernize-shrink-to-fit
       Replace	copy  and  swap	 tricks	 on  shrinkable	 containers  with  the
       shrink_to_fit() method call.

       The shrink_to_fit() method is more readable and more effective than the
       copy  and  swap trick to	reduce the capacity of a shrinkable container.
       Note that, the shrink_to_fit() method is	only available	in  C++11  and
       up.

   modernize-unary-static-assert
       The  check diagnoses any	static_assert declaration with an empty	string
       literal and provides a fix-it to	replace	the declaration	 with  a  sin-
       gle-argument static_assert declaration.

       The check is only applicable for	C++17 and later	code.

       The following code:

	  void f_textless(int a) {
	    static_assert(sizeof(a) <= 10, "");
	  }

       is replaced by:

	  void f_textless(int a) {
	    static_assert(sizeof(a) <= 10);
	  }

   modernize-use-auto
       This  check  is responsible for using the auto type specifier for vari-
       able declarations to improve code readability and maintainability.  For
       example:

	  std::vector<int>::iterator I = my_container.begin();

	  // transforms	to:

	  auto I = my_container.begin();

       The auto	type specifier will only be introduced in situations where the
       variable	type matches the type of the initializer expression. In	 other
       words  auto  should deduce the same type	that was originally spelled in
       the source.  However, not every situation should	be transformed:

	  int val = 42;
	  InfoStruct &I	= SomeObject.getInfo();

	  // Should not	become:

	  auto val = 42;
	  auto &I = SomeObject.getInfo();

       In this example using auto for builtins doesn't improve readability. In
       other  situations  it  makes  the  code less self-documenting impairing
       readability and maintainability.	As a result, auto is used only	intro-
       duced in	specific situations described below.

   Iterators
       Iterator	 type  specifiers  tend	 to be long and	used frequently, espe-
       cially in loop constructs. Since	 the  functions	 generating  iterators
       have  a	common	format,	the type specifier can be replaced without ob-
       scuring the meaning of code while improving readability	and  maintain-
       ability.

	  for (std::vector<int>::iterator I = my_container.begin(),
					  E = my_container.end();
	       I != E; ++I) {
	  }

	  // becomes

	  for (auto I =	my_container.begin(), E	= my_container.end(); I	!= E; ++I) {
	  }

       The  check  will	 only replace iterator type-specifiers when all	of the
       following conditions are	satisfied:

       o The iterator is for one of the	standard container in std namespace:

	 o array

	 o deque

	 o forward_list

	 o list

	 o vector

	 o map

	 o multimap

	 o set

	 o multiset

	 o unordered_map

	 o unordered_multimap

	 o unordered_set

	 o unordered_multiset

	 o queue

	 o priority_queue

	 o stack

       o The iterator is one of	the possible iterator types for	standard  con-
	 tainers:

	 o iterator

	 o reverse_iterator

	 o const_iterator

	 o const_reverse_iterator

       o In  addition to using iterator	types directly,	typedefs or other ways
	 of referring to those types are also  allowed.	 However,  implementa-
	 tion-specific	types for which	a type like std::vector<int>::iterator
	 is itself a typedef will not be transformed. Consider	the  following
	 examples:

	  // The following direct uses of iterator types will be transformed.
	  std::vector<int>::iterator I = MyVec.begin();
	  {
	    using namespace std;
	    list<int>::iterator	I = MyList.begin();
	  }

	  // The type specifier	for J would transform to auto since it's a typedef
	  // to	a standard iterator type.
	  typedef std::map<int,	std::string>::const_iterator map_iterator;
	  map_iterator J = MyMap.begin();

	  // The following implementation-specific iterator type for which
	  // std::vector<int>::iterator	could be a typedef would not be	transformed.
	  __gnu_cxx::__normal_iterator<int*, std::vector> K = MyVec.begin();

       o The  initializer for the variable being declared is not a braced ini-
	 tializer list.	Otherwise, use of auto would cause  the	 type  of  the
	 variable to be	deduced	as std::initializer_list.

   New expressions
       Frequently,  when  a  pointer is	declared and initialized with new, the
       pointee type is written twice: in the declaration type and in  the  new
       expression.  In	this  cases, the declaration type can be replaced with
       auto improving readability and maintainability.

	  TypeName *my_pointer = new TypeName(my_param);

	  // becomes

	  auto *my_pointer = new TypeName(my_param);

       The check will also replace the declaration type	in  multiple  declara-
       tions, if the following conditions are satisfied:

       o All  declared	variables  have	 the  same  type (i.e. all of them are
	 pointers to the same type).

       o All declared variables	are initialized	with a new expression.

       o The types of all the new expressions are the same than	the pointee of
	 the declaration type.

	  TypeName *my_first_pointer = new TypeName, *my_second_pointer	= new TypeName;

	  // becomes

	  auto *my_first_pointer = new TypeName, *my_second_pointer = new TypeName;

   Cast	expressions
       Frequently,  when  a  variable is declared and initialized with a cast,
       the variable type is written twice: in the declaration type and in  the
       cast  expression.  In  this cases, the declaration type can be replaced
       with auto improving readability and maintainability.

	  TypeName *my_pointer = static_cast<TypeName>(my_param);

	  // becomes

	  auto *my_pointer = static_cast<TypeName>(my_param);

       The  check  handles  static_cast,  dynamic_cast,	 const_cast,  reinter-
       pret_cast,  functional casts, C-style casts and function	templates that
       behave  as  casts,  such	 as  llvm::dyn_cast,  boost::lexical_cast  and
       gsl::narrow_cast.  Calls	to function templates are considered to	behave
       as casts	if the first template argument is explicit and is a type,  and
       the function returns that type, or a pointer or reference to it.

   Known Limitations
       o If  the  initializer is an explicit conversion	constructor, the check
	 will not replace the type specifier even though it would be  safe  to
	 do so.

       o User-defined iterators	are not	handled	at this	time.

   Options
       MinTypeNameLength
	      If the option is set to non-zero (default	5), the	check will ig-
	      nore type	names having a length less than	the option value.  The
	      option  affects expressions only,	not iterators.	Spaces between
	      multi-lexeme type	names (long int) are considered	 as  one.   If
	      RemoveStars  option  (see	 below)	is set to non-zero, then *s in
	      the type are also	counted	as a part of the type name.

	  // MinTypeNameLength = 0, RemoveStars=0

	  int a	= static_cast<int>(foo());	      // ---> auto a = ...
	  // length(bool *) = 4
	  bool *b = new	bool;			      // ---> auto *b =	...
	  unsigned c = static_cast<unsigned>(foo());  // ---> auto c = ...

	  // MinTypeNameLength = 5, RemoveStars=0

	  int a	= static_cast<int>(foo());		   // ---> int	a = ...
	  bool b = static_cast<bool>(foo());		   // ---> bool	b = ...
	  bool *pb = static_cast<bool*>(foo());		   // ---> bool	*pb = ...
	  unsigned c = static_cast<unsigned>(foo());	   // ---> auto	c = ...
	  // length(long <on-or-more-spaces> int) = 8
	  long int d = static_cast<long	int>(foo());	   // ---> auto	d = ...

	  // MinTypeNameLength = 5, RemoveStars=1

	  int a	= static_cast<int>(foo());		   // ---> int	a = ...
	  // length(int	* * ) =	5
	  int **pa = static_cast<int**>(foo());		   // ---> auto	pa = ...
	  bool b = static_cast<bool>(foo());		   // ---> bool	b = ...
	  bool *pb = static_cast<bool*>(foo());		   // ---> auto	pb = ...
	  unsigned c = static_cast<unsigned>(foo());	   // ---> auto	c = ...
	  long int d = static_cast<long	int>(foo());	   // ---> auto	d = ...

       RemoveStars
	      If the option is set to non-zero (default	is 0), the check  will
	      remove  stars  from the non-typedef pointer types	when replacing
	      type names with auto. Otherwise, the check will leave stars. For
	      example:

	  TypeName *my_first_pointer = new TypeName, *my_second_pointer	= new TypeName;

	  // RemoveStars = 0

	  auto *my_first_pointer = new TypeName, *my_second_pointer = new TypeName;

	  // RemoveStars = 1

	  auto my_first_pointer	= new TypeName,	my_second_pointer = new	TypeName;

   modernize-use-bool-literals
       Finds integer literals which are	cast to	bool.

	  bool p = 1;
	  bool f = static_cast<bool>(1);
	  std::ios_base::sync_with_stdio(0);
	  bool x = p ? 1 : 0;

	  // transforms	to

	  bool p = true;
	  bool f = true;
	  std::ios_base::sync_with_stdio(false);
	  bool x = p ? true : false;

   Options
       IgnoreMacros
	      If  set  to  non-zero,  the  check will not give warnings	inside
	      macros. Default is 1.

   modernize-use-default-member-init
       This check converts a default constructor's  member  initializers  into
       the new default member initializers in C++11. Other member initializers
       that match the default member initializer are removed. This can	reduce
       repeated	code or	allow use of '=	default'.

	  struct A {
	    A()	: i(5),	j(10.0)	{}
	    A(int i) : i(i), j(10.0) {}
	    int	i;
	    double j;
	  };

	  // becomes

	  struct A {
	    A()	{}
	    A(int i) : i(i) {}
	    int	i{5};
	    double j{10.0};
	  };

       NOTE:
	  Only	converts  member  initializers	for built-in types, enums, and
	  pointers.  The readability-redundant-member-init check  will	remove
	  redundant member initializers	for classes.

   Options
       UseAssignment
	      If this option is	set to non-zero	(default is 0),	the check will
	      initialise members with an assignment. For example:

	  struct A {
	    A()	{}
	    A(int i) : i(i) {}
	    int	i = 5;
	    double j = 10.0;
	  };

       IgnoreMacros
	      If this option is	set to non-zero	(default is 1),	the check will
	      not warn about members declared inside macros.

   modernize-use-emplace
       The  check  flags  insertions to	an STL-style container done by calling
       the push_back method with an explicitly-constructed  temporary  of  the
       container  element  type.  In this case,	the corresponding emplace_back
       method results in less verbose and  potentially	more  efficient	 code.
       Right  now  the	check  doesn't support push_front and insert.  It also
       doesn't support insert functions	for associative	containers because re-
       placing	insert	with  emplace  may  result in speed regression,	but it
       might get support with some addition flag in the	future.

       By default only	std::vector,  std::deque,  std::list  are  considered.
       This list can be	modified using the ContainersWithPushBack option.

       Before:

	  std::vector<MyClass> v;
	  v.push_back(MyClass(21, 37));

	  std::vector<std::pair<int, int>> w;

	  w.push_back(std::pair<int, int>(21, 37));
	  w.push_back(std::make_pair(21L, 37L));

       After:

	  std::vector<MyClass> v;
	  v.emplace_back(21, 37);

	  std::vector<std::pair<int, int>> w;
	  w.emplace_back(21, 37);
	  w.emplace_back(21L, 37L);

       By  default, the	check is able to remove	unnecessary std::make_pair and
       std::make_tuple calls from push_back calls on containers	 of  std::pair
       and  std::tuple.	 Custom	 tuple-like  types  can	 be  modified  by  the
       TupleTypes option;  custom  make	 functions  can	 be  modified  by  the
       TupleMakeFunctions option.

       The other situation is when we pass arguments that will be converted to
       a type inside a container.

       Before:

	  std::vector<boost::optional<std::string> > v;
	  v.push_back("abc");

       After:

	  std::vector<boost::optional<std::string> > v;
	  v.emplace_back("abc");

       In some cases the transformation	would be valid,	but the	code  wouldn't
       be  exception  safe.  In	 this case the calls of	push_back won't	be re-
       placed.

	  std::vector<std::unique_ptr<int>> v;
	  v.push_back(std::unique_ptr<int>(new int(0)));
	  auto *ptr = new int(1);
	  v.push_back(std::unique_ptr<int>(ptr));

       This is because replacing it with emplace_back could cause  a  leak  of
       this  pointer  if emplace_back would throw exception before emplacement
       (e.g. not enough	memory to add a	new element).

       For more	info read item 42 - "Consider emplacement  instead  of	inser-
       tion." of Scott Meyers "Effective Modern	C++".

       The  default  smart  pointers  that are considered are std::unique_ptr,
       std::shared_ptr,	std::auto_ptr. To  specify  other  smart  pointers  or
       other classes use the SmartPointers option.

       Check  also  doesn't fire if any	argument of the	constructor call would
       be:

	  o a bit-field	(bit-fields can't bind to rvalue/universal reference)

	  o a new expression (to avoid leak)

	  o if the argument would be converted via derived-to-base cast.

       This check requires C++11 or higher to run.

   Options
       ContainersWithPushBack
	      Semicolon-separated list of class	 names	of  custom  containers
	      that support push_back.

       IgnoreImplicitConstructors
	      When  non-zero, the check	will ignore implicitly constructed ar-
	      guments of push_back, e.g.

		 std::vector<std::string> v;
		 v.push_back("a"); // Ignored when IgnoreImplicitConstructors is ``1``.

	      Default is 0.

       SmartPointers
	      Semicolon-separated list of class	names of custom	 smart	point-
	      ers.

       TupleTypes
	      Semicolon-separated list of std::tuple-like class	names.

       TupleMakeFunctions
	      Semicolon-separated list of std::make_tuple-like function	names.
	      Those function calls will	be removed from	 push_back  calls  and
	      turned into emplace_back.

   Example
	  std::vector<MyTuple<int, bool, char>>	x;
	  x.push_back(MakeMyTuple(1, false, 'x'));

       transforms to:

	  std::vector<MyTuple<int, bool, char>>	x;
	  x.emplace_back(1, false, 'x');

       when  TupleTypes	 is  set  to  MyTuple and TupleMakeFunctions is	set to
       MakeMyTuple.

   modernize-use-equals-default
       This check replaces default bodies of special member functions  with  =
       default;.  The  explicitly  defaulted function declarations enable more
       opportunities in	optimization, because the compiler might treat explic-
       itly defaulted functions	as trivial.

	  struct A {
	    A()	{}
	    ~A();
	  };
	  A::~A() {}

	  // becomes

	  struct A {
	    A()	= default;
	    ~A();
	  };
	  A::~A() = default;

       NOTE:
	  Move-constructor and move-assignment operator	are not	supported yet.

   Options
       IgnoreMacros
	      If  set  to  non-zero,  the  check will not give warnings	inside
	      macros. Default is 1.

   modernize-use-equals-delete
       This check marks	unimplemented private special member functions with  =
       delete.	 To avoid false-positives, this	check only applies in a	trans-
       lation unit that	has all	other member functions implemented.

	  struct A {
	  private:
	    A(const A&);
	    A& operator=(const A&);
	  };

	  // becomes

	  struct A {
	  private:
	    A(const A&)	= delete;
	    A& operator=(const A&) = delete;
	  };

       IgnoreMacros
	      If this option is	set to non-zero	(default is 1),	the check will
	      not warn about functions declared	inside macros.

   modernize-use-nodiscard
       Adds [[nodiscard]] attributes (introduced in C++17) to member functions
       in order	to highlight at	compile	time which return values should	not be
       ignored.

       Member functions	need to	satisfy	the following conditions to be consid-
       ered by this check:

	  o no	[[nodiscard]],	[[noreturn]],	__attribute__((warn_unused_re-
	    sult)),  [[clang::warn_unused_result]]  nor	[[gcc::warn_unused_re-
	    sult]] attribute,

	  o non-void return type,

	  o non-template return	types,

	  o const member function,

	  o non-variadic functions,

	  o no non-const reference parameters,

	  o no pointer parameters,

	  o no template	parameters,

	  o no template	function parameters,

	  o not	be a member of a class with mutable member variables,

	  o no Lambdas,

	  o no conversion functions.

       Such functions have no means of altering	any state  or  passing	values
       other  than via the return type.	Unless the member functions are	alter-
       ing state via some external call	(e.g. I/O).

   Example
	  bool empty() const;
	  bool empty(int i) const;

       transforms to:

	  [[nodiscard] bool empty() const;
	  [[nodiscard] bool empty(int i) const;

   Options
       ReplacementString
	      Specifies	a macro	to use instead of [[nodiscard]]. This is  use-
	      ful  when	 maintaining  source code that needs to	compile	with a
	      pre-C++17	compiler.

   Example
	  bool empty() const;
	  bool empty(int i) const;

       transforms to:

	  NO_DISCARD bool empty() const;
	  NO_DISCARD bool empty(int i) const;

       if the ReplacementString	option is set to NO_DISCARD.

       NOTE:
	  If the ReplacementString is not  a  C++  attribute,  but  instead  a
	  macro,  then	that macro must	be defined in scope or the fix-it will
	  not be applied.

       NOTE:
	  For alternative __attribute__	syntax options to  mark	 functions  as
	  [[nodiscard]]	     in	     non-c++17	    source	code.	   See
	  https://clang.llvm.org/docs/AttributeReference.html#nodiscard-warn-unused-result

   modernize-use-noexcept
       This  check  replaces  deprecated dynamic exception specifications with
       the appropriate noexcept	specification (introduced in C++11).   By  de-
       fault  this check will replace throw() with noexcept, and throw(<excep-
       tion>[,...]) or throw(...) with noexcept(false).

   Example
	  void foo() throw();
		void bar() throw(int) {}

       transforms to:

	  void foo() noexcept;
		void bar() noexcept(false) {}

   Options
       ReplacementString

       Users can use ReplacementString to specify a macro to  use  instead  of
       noexcept.  This is useful when maintaining source code that uses	custom
       exception specification marking other than noexcept.  Fix-it hints will
       only be generated for non-throwing specifications.

   Example
	  void bar() throw(int);
	  void foo() throw();

       transforms to:

	  void bar() throw(int);  // No	fix-it generated.
	  void foo() NOEXCEPT;

       if the ReplacementString	option is set to NOEXCEPT.

       UseNoexceptFalse

       Enabled	by  default,  disabling	will generate fix-it hints that	remove
       throwing	dynamic	exception specs, e.g., throw(<something>),  completely
       without providing a replacement text, except for	destructors and	delete
       operators that are noexcept(true) by default.

   Example
	  void foo() throw(int)	{}

	  struct bar {
	    void foobar() throw(int);
	    void operator delete(void *ptr) throw(int);
	    void operator delete[](void	*ptr) throw(int);
	    ~bar() throw(int);
	  }

       transforms to:

	  void foo() {}

	  struct bar {
	    void foobar();
	    void operator delete(void *ptr) noexcept(false);
	    void operator delete[](void	*ptr) noexcept(false);
	    ~bar() noexcept(false);
	  }

       if the UseNoexceptFalse option is set to	0.

   modernize-use-nullptr
       The check converts the usage of null pointer constants (eg. NULL, 0) to
       use the new C++11 nullptr keyword.

   Example
	  void assignment() {
	    char *a = NULL;
	    char *b = 0;
	    char c = 0;
	  }

	  int *ret_ptr() {
	    return 0;
	  }

       transforms to:

	  void assignment() {
	    char *a = nullptr;
	    char *b = nullptr;
	    char c = 0;
	  }

	  int *ret_ptr() {
	    return nullptr;
	  }

   Options
       NullMacros
	      Comma-separated  list  of	 macro	names that will	be transformed
	      along with NULL. By default this check  will  only  replace  the
	      NULL macro and will skip any similar user-defined	macros.

   Example
	  #define MY_NULL (void*)0
	  void assignment() {
	    void *p = MY_NULL;
	  }

       transforms to:

	  #define MY_NULL NULL
	  void assignment() {
	    int	*p = nullptr;
	  }

       if the NullMacros option	is set to MY_NULL.

   modernize-use-override
       Adds override (introduced in C++11) to overridden virtual functions and
       removes virtual from those functions as it is not required.

       virtual on non base class implementations was used to help indiciate to
       the  user  that	a  function was	virtual. C++ compilers did not use the
       presence	of this	to signify an overriden	function.

       In C++ 11 override and final keywords were introduced to	allow overrid-
       den functions to	be marked appropriately. Their presence	allows compil-
       ers to verify that an overridden	function correctly  overrides  a  base
       class implementation.

       This can	be useful as compilers can generate a compile time error when:

	  o The	base class implementation function signature changes.

	  o The	user has not created the override with the correct signature.

   Options
       IgnoreDestructors
	      If  set  to  non-zero, this check	will not diagnose destructors.
	      Default is 0.

       OverrideSpelling
	      Specifies	a macro	to use instead of  override.  This  is	useful
	      when  maintaining	 source	code that also needs to	compile	with a
	      pre-C++11	compiler.

       FinalSpelling
	      Specifies	a macro	to use instead of final. This is  useful  when
	      maintaining  source  code	 that  also  needs  to	compile	with a
	      pre-C++11	compiler.

       NOTE:
	  For	more   information   on	   the	  use	 of    override	   see
	  https://en.cppreference.com/w/cpp/language/override

   modernize-use-trailing-return-type
       Rewrites	 function signatures to	use a trailing return type (introduced
       in C++11). This transformation is purely	stylistic.   The  return  type
       before  the  function  name  is replaced	by auto	and inserted after the
       function	parameter list (and qualifiers).

   Example
	  int f1();
	  inline int f2(int arg) noexcept;
	  virtual float	f3() const && =	delete;

       transforms to:

	  auto f1() -> int;
	  inline auto f2(int arg) -> int noexcept;
	  virtual auto f3() const && ->	float =	delete;

   Known Limitations
       The following categories	of return types	cannot be rewritten currently:
       *  function pointers * member function pointers * member	pointers * de-
       cltype, when it is the top level	expression

       Unqualified names in the	return type might erroneously refer to differ-
       ent entities after the rewrite.	Preventing such	errors requires	a full
       lookup of all unqualified names present in the return type in the scope
       of  the	trailing  return  type	location.  This	location includes e.g.
       function	parameter names	and members of the enclosing class  (including
       all inherited classes).	Such a lookup is currently not implemented.

       Given the following piece of code

	  struct Object	{ long long value; };
	  Object f(unsigned Object) { return {Object * 2}; }
	  class	CC {
	    int	Object;
	    struct Object m();
	  };
	  Object CC::m() { return {0}; }

       a careless rewrite would	produce	the following output:

	  struct Object	{ long long value; };
	  auto f(unsigned Object) -> Object { return {Object * 2}; } //	error
	  class	CC {
	    int	Object;
	    auto m() ->	struct Object;
	  };
	  auto CC::m() -> Object { return {0}; } // error

       This  code  fails  to  compile  because	the Object in the context of f
       refers to the equally named function parameter.	Similarly, the	Object
       in  the	context	 of  m	refers to the equally named class member.  The
       check can currently only	detect a clash with a function parameter name.

   modernize-use-transparent-functors
       Prefer transparent functors to non-transparent ones. When using	trans-
       parent  functors,  the  type  does not need to be repeated. The code is
       easier to read, maintain	and less prone to errors. It is	 not  possible
       to introduce unwanted conversions.

	  // Non-transparent functor
	  std::map<int,	std::string, std::greater<int>>	s;

	  // Transparent functor.
	  std::map<int,	std::string, std::greater<>> s;

	  // Non-transparent functor
	  using	MyFunctor = std::less<MyType>;

       It  is not always a safe	transformation though. The following case will
       be untouched to preserve	the semantics.

	  // Non-transparent functor
	  std::map<const char *, std::string, std::greater<std::string>> s;

   Options
       SafeMode
	      If the option is set to non-zero,	the check  will	 not  diagnose
	      cases  where using a transparent functor cannot be guaranteed to
	      produce identical	results	as  the	 original  code.  The  default
	      value for	this option is 0.

       This check requires using C++14 or higher to run.

   modernize-use-uncaught-exceptions
       This  check  will  warn on calls	to std::uncaught_exception and replace
       them with calls to std::uncaught_exceptions, since std::uncaught_excep-
       tion was	deprecated in C++17.

       Below  are a few	examples of what kind of occurrences will be found and
       what they will be replaced with.

	  #define MACRO1 std::uncaught_exception
	  #define MACRO2 std::uncaught_exception

	  int uncaught_exception() {
		  return 0;
	  }

	  int main() {
		  int res;

	    res	= uncaught_exception();
	    // No warning, since it is not the deprecated function from	namespace std

	    res	= MACRO2();
	    // Warning,	but will not be	replaced

	    res	= std::uncaught_exception();
	    // Warning and replaced

	    using std::uncaught_exception;
	    // Warning and replaced

	    res	= uncaught_exception();
	    // Warning and replaced
	  }

       After applying the fixes	the code will look like	the following:

	  #define MACRO1 std::uncaught_exception
	  #define MACRO2 std::uncaught_exception

	  int uncaught_exception() {
		  return 0;
	  }

	  int main() {
	    int	res;

	    res	= uncaught_exception();

	    res	= MACRO2();

	    res	= std::uncaught_exceptions();

	    using std::uncaught_exceptions;

	    res	= uncaught_exceptions();
	  }

   modernize-use-using
       The check converts the usage of typedef with using keyword.

       Before:

	  typedef int variable;

	  class	Class{};
	  typedef void (Class::* MyPtrType)() const;

       After:

	  using	variable = int;

	  class	Class{};
	  using	MyPtrType = void (Class::*)() const;

       This check requires using C++11 or higher to run.

   Options
       IgnoreMacros
	      If set to	non-zero, the check  will  not	give  warnings	inside
	      macros. Default is 1.

   mpi-buffer-deref
       This  check  verifies if	a buffer passed	to an MPI (Message Passing In-
       terface)	function  is  sufficiently  dereferenced.  Buffers  should  be
       passed as a single pointer or array. As MPI function signatures specify
       void * for their	buffer types, insufficiently dereferenced buffers  can
       be  passed, like	for example as double pointers or multidimensional ar-
       rays, without a compiler	warning	emitted.

       Examples:

	  // A double pointer is passed	to the MPI function.
	  char *buf;
	  MPI_Send(&buf, 1, MPI_CHAR, 0, 0, MPI_COMM_WORLD);

	  // A multidimensional	array is passed	to the MPI function.
	  short	buf[1][1];
	  MPI_Send(buf,	1, MPI_SHORT, 0, 0, MPI_COMM_WORLD);

	  // A pointer to an array is passed to	the MPI	function.
	  short	*buf[1];
	  MPI_Send(buf,	1, MPI_SHORT, 0, 0, MPI_COMM_WORLD);

   mpi-type-mismatch
       This check verifies if buffer type and MPI (Message Passing  Interface)
       datatype	 pairs match for used MPI functions. All MPI datatypes defined
       by the MPI standard (3.1) are verified  by  this	 check.	 User  defined
       typedefs,  custom MPI datatypes and null	pointer	constants are skipped,
       in the course of	verification.

       Example:

	  // In	this case, the buffer type matches MPI datatype.
	  char buf;
	  MPI_Send(&buf, 1, MPI_CHAR, 0, 0, MPI_COMM_WORLD);

	  // In	the following case, the	buffer type does not match MPI datatype.
	  int buf;
	  MPI_Send(&buf, 1, MPI_CHAR, 0, 0, MPI_COMM_WORLD);

   objc-avoid-nserror-init
       Finds improper initialization of	NSError	objects.

       According to Apple developer document, we  should  always  use  factory
       method errorWithDomain:code:userInfo: to	create new NSError objects in-
       stead of	[NSError alloc]	init]. Otherwise it will  lead	to  a  warning
       message during runtime.

       The     corresponding	 information	 about	  NSError    creation:
       https://developer.apple.com/library/content/documentation/Cocoa/Conceptual/ErrorHandlingCocoa/CreateCustomizeNSError/CreateCustomizeNSError.html

   objc-avoid-spinlock
       Finds  usages of	OSSpinlock, which is deprecated	due to potential live-
       lock problems.

       This check will detect following	function invocations:

       o OSSpinlockLock

       o OSSpinlockTry

       o OSSpinlockUnlock

       The  corresponding  information	about  the  problem   of   OSSpinlock:
       https://blog.postmates.com/why-spinlocks-are-bad-on-ios-b69fc5221058

   objc-forbidden-subclassing
       Finds Objective-C classes which are subclasses of classes which are not
       designed	to be subclassed.

       By default, includes a list of Objective-C classes which	 are  publicly
       documented as not supporting subclassing.

       NOTE:
	  Instead of using this	check, for code	under your control, you	should
	  add __attribute__((objc_subclassing_restricted)) before your @inter-
	  face	declarations  to ensure	the compiler prevents others from sub-
	  classing	  your	      Objective-C	 classes.	   See
	  https://clang.llvm.org/docs/AttributeReference.html#objc-subclassing-restricted

   Options
       ForbiddenSuperClassNames
	      Semicolon-separated list of names	of Objective-C	classes	 which
	      do not support subclassing.

	      Defaults	to ABNewPersonViewController;ABPeoplePickerNavigation-
	      Controller;ABPersonViewController;ABUnknownPersonViewCon-
	      troller;NSHashTable;NSMapTable;NSPointerArray;NSPointerFunc-
	      tions;NSTimer;UIActionSheet;UIAlertView;UIImagePickerCon-
	      troller;UITextInputMode;UIWebView.

   objc-property-declaration
       Finds property declarations in Objective-C files	that do	not follow the
       pattern of property names in Apple's programming	 guide.	 The  property
       name should be in the format of Lower Camel Case.

       For code:

	  @property(nonatomic, assign) int LowerCamelCase;

       The fix will be:

	  @property(nonatomic, assign) int lowerCamelCase;

       The check will only fix 'CamelCase' to 'camelCase'. In some other cases
       we will only provide warning messages since the property	name could  be
       complicated.   Users  will  need	to come	up with	a proper name by their
       own.

       This check also accepts special acronyms	as prefixes or suffixes.  Such
       prefixes	or suffixes will suppress the Lower Camel Case check according
       to			       the				guide:
       https://developer.apple.com/library/content/documentation/Cocoa/Conceptual/CodingGuidelines/Articles/NamingBasics.html#//apple_ref/doc/uid/20001281-1002931-BBCFHEAB

       For	a      full	 list	   of	    well-known	     acronyms:
       https://developer.apple.com/library/content/documentation/Cocoa/Conceptual/CodingGuidelines/Articles/APIAbbreviations.html#//apple_ref/doc/uid/20001285-BCIHCGAE

       The		 corresponding		     style		 rule:
       https://developer.apple.com/library/content/documentation/Cocoa/Conceptual/CodingGuidelines/Articles/NamingIvarsAndTypes.html#//apple_ref/doc/uid/20001284-1001757

       The check will also accept property declared in category	with a	prefix
       of  lowercase  letters  followed	by a '_' to avoid naming conflict. For
       example:

	  @property(nonatomic, assign) int abc_lowerCamelCase;

       The		 corresponding		     style		 rule:
       https://developer.apple.com/library/content/qa/qa1908/_index.html

   objc-super-self
       Finds  invocations  of -self on super instances in initializers of sub-
       classes of NSObject and recommends calling a superclass initializer in-
       stead.

       Invoking	 -self on super	instances in initializers is a common program-
       mer error when the programmer's original	intent is to call a superclass
       initializer.  Failing  to call a	superclass initializer breaks initial-
       izer chaining and can result in invalid object initialization.

   openmp-exception-escape
       Analyzes	OpenMP Structured Blocks and checks that no exception  escapes
       out of the Structured Block it was thrown in.

       As  per	the  OpenMP specification, a structured	block is an executable
       statement, possibly compound, with a single entry at the	top and	a sin-
       gle exit	at the bottom. Which means, throw may not be used to to	'exit'
       out of the structured block. If an exception is not caught in the  same
       structured block	it was thrown in, the behaviour	is undefined.

       FIXME: this check does not model	SEH, setjmp/longjmp.

       WARNING!	This check may be expensive on large source files.

   Options
       IgnoredExceptions
	      Comma-separated list containing type names which are not counted
	      as thrown	exceptions in the check. Default  value	 is  an	 empty
	      string.

   openmp-use-default-none
       Finds  OpenMP  directives that are allowed to contain a default clause,
       but either don't	specify	it or the clause is  specified	but  with  the
       kind other than none, and suggests to use the default(none) clause.

       Using default(none) clause forces developers to explicitly specify data
       sharing attributes for the variables referenced in the construct,  thus
       making  it  obvious  which  variables are referenced, and what is their
       data sharing attribute, thus increasing readability and possibly	making
       errors easier to	spot.

   Example
	  // ``for`` directive can not have ``default``	clause,	no diagnostics.
	  void n0(const	int a) {
	  #pragma omp for
	    for	(int b = 0; b <	a; b++)
	      ;
	  }

	  // ``parallel`` directive.

	  // ``parallel`` directive can	have ``default`` clause, but said clause is not
	  // specified,	diagnosed.
	  void p0_0() {
	  #pragma omp parallel
	    ;
	    // WARNING:	OpenMP directive ``parallel`` does not specify ``default``
	    //		clause.	Consider specifying ``default(none)`` clause.
	  }

	  // ``parallel`` directive can	have ``default`` clause, and said clause is
	  // specified,	with ``none`` kind, all	good.
	  void p0_1() {
	  #pragma omp parallel default(none)
	    ;
	  }

	  // ``parallel`` directive can	have ``default`` clause, and said clause is
	  // specified,	but with ``shared`` kind, which	is not ``none``, diagnose.
	  void p0_2() {
	  #pragma omp parallel default(shared)
	    ;
	    // WARNING:	OpenMP directive ``parallel`` specifies	``default(shared)``
	    //		clause.	Consider using ``default(none)`` clause	instead.
	  }

   performance-faster-string-find
       Optimize	 calls	to  std::string::find()	 and  friends  when the	needle
       passed is a single character  string  literal.  The  character  literal
       overload	is more	efficient.

       Examples:

	  str.find("A");

	  // becomes

	  str.find('A');

   Options
       StringLikeClasses
	      Semicolon-separated list of names	of string-like classes.	By de-
	      fault only std::basic_string is considered. The list of  methods
	      to consired is fixed.

   performance-for-range-copy
       Finds C++11 for ranges where the	loop variable is copied	in each	itera-
       tion but	it would suffice to obtain it by const reference.

       The check is only applied to loop variables of types that are expensive
       to copy which means they	are not	trivially copyable or have a non-triv-
       ial copy	constructor or destructor.

       To ensure that it is safe to replace the	copy with  a  const  reference
       the following heuristic is employed:

       1. The loop variable is const qualified.

       2. The  loop variable is	not const, but only const methods or operators
	  are invoked on it, or	it is used as const reference or  value	 argu-
	  ment in constructors or function calls.

   Options
       WarnOnAllAutoCopies
	      When  non-zero,  warns  on  any  use  of auto as the type	of the
	      range-based for loop variable. Default is	0.

       AllowedTypes
	      A	semicolon-separated list of  names  of	types  allowed	to  be
	      copied in	each iteration.	Regular	expressions are	accepted, e.g.
	      [Rr]ef(erence)?$ matches every type with suffix Ref, ref,	Refer-
	      ence and reference. The default is empty.

   performance-implicit-conversion-in-loop
       This  warning  appears  in  a  range-based loop with a loop variable of
       const ref type where the	type of	the variable does not  match  the  one
       returned	 by  the iterator. This	means that an implicit conversion hap-
       pens, which can for example result in expensive deep copies.

       Example:

	  map<int, vector<string>> my_map;
	  for (const pair<int, vector<string>>&	p : my_map) {}
	  // The iterator type is in fact pair<const int, vector<string>>, which means
	  // that the compiler added a conversion, resulting in	a copy of the vectors.

       The easiest solution is usually to use const auto& instead  of  writing
       the type	manually.

   performance-inefficient-algorithm
       Warns on	inefficient use	of STL algorithms on associative containers.

       Associative  containers	implements  some  of the algorithms as methods
       which should be preferred to the	algorithms in  the  algorithm  header.
       The methods can take advanatage of the order of the elements.

	  std::set<int>	s;
	  auto it = std::find(s.begin(), s.end(), 43);

	  // becomes

	  auto it = s.find(43);

	  std::set<int>	s;
	  auto c = std::count(s.begin(), s.end(), 43);

	  // becomes

	  auto c = s.count(43);

   performance-inefficient-string-concatenation
       This  check  warns about	the performance	overhead arising from concate-
       nating strings using the	operator+, for instance:

	  std::string a("Foo"),	b("Bar");
	  a = a	+ b;

       Instead of this structure you should use	 operator+=  or	 std::string's
       (std::basic_string) class member	function append(). For instance:

	  std::string a("Foo"),	b("Baz");
	  for (int i = 0; i < 20000; ++i) {
	      a	= a + "Bar" + b;
	  }

       Could be	rewritten in a greatly more efficient way like:

	  std::string a("Foo"),	b("Baz");
	  for (int i = 0; i < 20000; ++i) {
	      a.append("Bar").append(b);
	  }

       And this	can be rewritten too:

	  void f(const std::string&) {}
	  std::string a("Foo"),	b("Baz");
	  void g() {
	      f(a + "Bar" + b);
	  }

       In a slightly more efficient way	like:

	  void f(const std::string&) {}
	  std::string a("Foo"),	b("Baz");
	  void g() {
	      f(std::string(a).append("Bar").append(b));
	  }

   Options
       StrictMode
	      When  zero, the check will only check the	string usage in	while,
	      for and for-range	statements. Default is 0.

   performance-inefficient-vector-operation
       Finds possible inefficient std::vector operations (e.g. push_back,  em-
       place_back) that	may cause unnecessary memory reallocations.

       Currently,  the check only detects following kinds of loops with	a sin-
       gle statement body:

       o Counter-based for loops start with 0:

	  std::vector<int> v;
	  for (int i = 0; i < n; ++i) {
	    v.push_back(n);
	    // This will trigger the warning since the push_back may cause multiple
	    // memory reallocations in v. This can be avoid by inserting a 'reserve(n)'
	    // statement before	the for	statement.
	  }

       o For-range loops like for (range-declaration : range_expression),  the
	 type  of range_expression can be std::vector, std::array, std::deque,
	 std::set, std::unordered_set, std::map, std::unordered_set:

	  std::vector<int> data;
	  std::vector<int> v;

	  for (auto element : data) {
	    v.push_back(element);
	    // This will trigger the warning since the 'push_back' may cause multiple
	    // memory reallocations in v. This can be avoid by inserting a
	    // 'reserve(data.size())' statement	before the for statement.
	  }

   Options
       VectorLikeClasses
	      Semicolon-separated list of names	of vector-like classes.	By de-
	      fault only ::std::vector is considered.

   performance-move-const-arg
       The check warns

       o if std::move()	is called with a constant argument,

       o if  std::move()  is  called  with an argument of a trivially-copyable
	 type,

       o if the	result of std::move() is passed	as a const reference argument.

       In all three cases, the check will  suggest  a  fix  that  removes  the
       std::move().

       Here are	examples of each of the	three cases:

	  const	string s;
	  return std::move(s);	// Warning: std::move of the const variable has	no effect

	  int x;
	  return std::move(x);	// Warning: std::move of the variable of a trivially-copyable type has no effect

	  void f(const string &s);
	  string s;
	  f(std::move(s));  // Warning:	passing	result of std::move as a const reference argument; no move will	actually happen

   Options
       CheckTriviallyCopyableMove
	      If  non-zero, enables detection of trivially copyable types that
	      do not have a move constructor. Default is non-zero.

   performance-move-constructor-init
       "cert-oop11-cpp"	redirects here as an alias for this check.

       The check flags user-defined move constructors that  have  a  ctor-ini-
       tializer	initializing a member or base class through a copy constructor
       instead of a move constructor.

   Options
       IncludeStyle
	      A	string specifying which	include-style is used, llvm or google.
	      Default is llvm.

   performance-noexcept-move-constructor
       The check flags user-defined move constructors and assignment operators
       not marked with noexcept	or marked with noexcept(expr) where expr eval-
       uates to	false (but is not a false literal itself).

       Move  constructors of all the types used	with STL containers, for exam-
       ple, need to be declared	noexcept. Otherwise STL	will choose copy  con-
       structors instead. The same is valid for	move assignment	operations.

   performance-type-promotion-in-math-fn
       Finds calls to C	math library functions (from math.h or,	in C++,	cmath)
       with implicit float to double promotions.

       For example, warns on ::sin(0.f), because this funciton's parameter  is
       a  double.  You	probably  meant	 to  call  std::sin(0.f)  (in C++), or
       sinf(0.f) (in C).

	  float	a;
	  asin(a);

	  // becomes

	  float	a;
	  std::asin(a);

   performance-unnecessary-copy-initialization
       Finds local variable declarations that are initialized using  the  copy
       constructor  of	a  non-trivially-copyable type but it would suffice to
       obtain a	const reference.

       The check is only applied if it is safe to replace the copy by a	 const
       reference.  This	 is  the  case when the	variable is const qualified or
       when it is only used as a const,	i.e. only const	methods	 or  operators
       are  invoked  on	it, or it is used as const reference or	value argument
       in constructors or function calls.

       Example:

	  const	string&	constReference();
	  void Function() {
	    // The warning will	suggest	making this a const reference.
	    const string UnnecessaryCopy = constReference();
	  }

	  struct Foo {
	    const string& name() const;
	  };
	  void Function(const Foo& foo)	{
	    // The warning will	suggest	making this a const reference.
	    string UnnecessaryCopy1 = foo.name();
	    UnnecessaryCopy1.find("bar");

	    // The warning will	suggest	making this a const reference.
	    string UnnecessaryCopy2 = UnnecessaryCopy1;
	    UnnecessaryCopy2.find("bar");
	  }

   Options
       AllowedTypes
	      A	semicolon-separated list of names of types allowed to be  ini-
	      tialized	by  copying.  Regular  expressions  are	accepted, e.g.
	      [Rr]ef(erence)?$ matches every type with suffix Ref, ref,	Refer-
	      ence and reference. The default is empty.

   performance-unnecessary-value-param
       Flags  value parameter declarations of expensive	to copy	types that are
       copied for each invocation but it would suffice to pass them  by	 const
       reference.

       The  check is only applied to parameters	of types that are expensive to
       copy which means	they are not trivially copyable	or have	a  non-trivial
       copy constructor	or destructor.

       To  ensure  that	it is safe to replace the value	parameter with a const
       reference the following heuristic is employed:

       1. the parameter	is const qualified;

       2. the parameter	is not const, but only const methods or	operators  are
	  invoked on it, or it is used as const	reference or value argument in
	  constructors or function calls.

       Example:

	  void f(const string Value) {
	    // The warning will	suggest	making Value a reference.
	  }

	  void g(ExpensiveToCopy Value)	{
	    // The warning will	suggest	making Value a const reference.
	    Value.ConstMethd();
	    ExpensiveToCopy Copy(Value);
	  }

       If the parameter	is not const, only copied or assigned once and	has  a
       non-trivial  move-constructor  or move-assignment operator respectively
       the check will suggest to move it.

       Example:

	  void setValue(string Value) {
	    Field = Value;
	  }

       Will become:

	  #include <utility>

	  void setValue(string Value) {
	    Field = std::move(Value);
	  }

   Options
       IncludeStyle
	      A	string specifying which	include-style is used, llvm or google.
	      Default is llvm.

       AllowedTypes
	      A	 semicolon-separated  list  of	names  of  types allowed to be
	      passed  by  value.   Regular  expressions	 are  accepted,	  e.g.
	      [Rr]ef(erence)?$ matches every type with suffix Ref, ref,	Refer-
	      ence and reference. The default is empty.

   portability-simd-intrinsics
       Finds SIMD intrinsics calls  and	 suggests  std::experimental::simd  (-
       P0214) alternatives.

       If the option Suggest is	set to non-zero, for

	  _mm_add_epi32(a, b); // x86
	  vec_add(a, b);       // Power

       the check suggests an alternative: operator+ on std::experimental::simd
       objects.

       Otherwise, it just complains the	intrinsics are non-portable (and there
       are P0214 alternatives).

       Many architectures provide SIMD operations (e.g.	x86 SSE/AVX, Power Al-
       tiVec/VSX, ARM NEON). It	is common that SIMD code implementing the same
       algorithm, is written in	multiple target-dispatching pieces to optimize
       for different architectures or micro-architectures.

       The C++ standard	proposal P0214 and its extensions  cover  many	common
       SIMD operations.	By migrating from target-dependent intrinsics to P0214
       operations, the SIMD code can be	simplified and	pieces	for  different
       targets can be unified.

       Refer  to  P0214	 for introduction and motivation for the data-parallel
       standard	library.

   Options
       Suggest
	      If this option is	set to non-zero	(default is 0),	the check will
	      suggest P0214 alternatives, otherwise it only points out the in-
	      trinsic function is non-portable.

       Std    The namespace used to suggest P0214 alternatives.	If not	speci-
	      fied,   std::   for   -std=c++2a	 and  std::experimental::  for
	      -std=c++11.

   readability-avoid-const-params-in-decls
       Checks whether a	function declaration has parameters that are top level
       const.

       const values in declarations do not affect the signature	of a function,
       so they should not be put there.

       Examples:

	  void f(const string);	  // Bad: const	is top level.
	  void f(const string&);  // Good: const is not	top level.

   readability-braces-around-statements
       google-readability-braces-around-statements redirects here as an	 alias
       for this	check.

       Checks  that  bodies  of	 if  statements	 and loops (for, do while, and
       while) are inside braces.

       Before:

	  if (condition)
	    statement;

       After:

	  if (condition) {
	    statement;
	  }

   Options
       ShortStatementLines
	      Defines the minimal number of lines that	the  statement	should
	      have in order to trigger this check.

	      The number of lines is counted from the end of condition or ini-
	      tial keyword (do/else) until the last line of the	 inner	state-
	      ment.  Default  value  0	means that braces will be added	to all
	      statements (not having them already).

   readability-const-return-type
       Checks for functions with a const-qualified return type and  recommends
       removal of the const keyword. Such use of const is usually superfluous,
       and can prevent valuable	compiler optimizations.	 Does  not  (yet)  fix
       trailing	return types.

       Examples:

	  const	int foo();
	  const	Clazz foo();
	  Clazz	*const foo();

       Note  that  this	applies	strictly to top-level qualification, which ex-
       cludes pointers or references to	const values. For example,  these  are
       fine:

	  const	int* foo();
	  const	int& foo();
	  const	Clazz* foo();

   readability-container-size-empty
       Checks  whether a call to the size() method can be replaced with	a call
       to empty().

       The emptiness of	a container should be checked using the	empty()	method
       instead	of  the	 size()	 method. It is not guaranteed that size() is a
       constant-time function, and it is generally  more  efficient  and  also
       shows  clearer  intent  to use empty(). Furthermore some	containers may
       implement the empty() method but	not implement the size() method. Using
       empty()	whenever  possible  makes  it easier to	switch to another con-
       tainer in the future.

       The check issues	warning	if a container has size() and empty()  methods
       matching	following signatures:

	  size_type size() const;
	  bool empty() const;

       size_type can be	any kind of integer type.

   readability-convert-member-functions-to-static
       Finds  non-static  member functions that	can be made static because the
       functions don't use this.

       After applying modifications as suggested by  the  check,  runnnig  the
       check  again  might  find  more	opportunities to mark member functions
       static.

       After making a member function static, you might	want to	run the	 check
       readability-static-accessed-through-instance  to	replace	calls like In-
       stance.method() by Class::method().

   readability-delete-null-pointer
       Checks the if statements	where a	pointer's  existence  is  checked  and
       then  deletes the pointer.  The check is	unnecessary as deleting	a null
       pointer has no effect.

	  int *p;
	  if (p)
	    delete p;

   readability-deleted-default
       Checks that constructors	and assignment operators marked	as  =  default
       are not actually	deleted	by the compiler.

	  class	Example	{
	  public:
	    // This constructor	is deleted because I is	missing	a default value.
	    Example() =	default;
	    // This is fine.
	    Example(const Example& Other) = default;
	    // This operator is	deleted	because	I cannot be assigned (it is const).
	    Example& operator=(const Example& Other) = default;

	  private:
	    const int I;
	  };

   readability-else-after-return
       LLVM  Coding Standards advises to reduce	indentation where possible and
       where it	makes understanding code easier.  Early	exit  is  one  of  the
       suggested enforcements of that. Please do not use else or else if after
       something that interrupts control flow -	like return, break,  continue,
       throw.

       The following piece of code illustrates how the check works. This piece
       of code:

	  void foo(int Value) {
	    int	Local =	0;
	    for	(int i = 0; i <	42; i++) {
	      if (Value	== 1) {
		return;
	      }	else {
		Local++;
	      }

	      if (Value	== 2)
		continue;
	      else
		Local++;

	      if (Value	== 3) {
		throw 42;
	      }	else {
		Local++;
	      }
	    }
	  }

       Would be	transformed into:

	  void foo(int Value) {
	    int	Local =	0;
	    for	(int i = 0; i <	42; i++) {
	      if (Value	== 1) {
		return;
	      }
	      Local++;

	      if (Value	== 2)
		continue;
	      Local++;

	      if (Value	== 3) {
		throw 42;
	      }
	      Local++;
	    }
	  }

       This check helps	to enforce this	LLVM Coding Standards recommendation.

   readability-function-size
       google-readability-function-size	redirects here as an  alias  for  this
       check.

       Checks for large	functions based	on various metrics.

   Options
       LineThreshold
	      Flag functions exceeding this number of lines. The default is -1
	      (ignore the number of lines).

       StatementThreshold
	      Flag functions exceeding this number  of	statements.  This  may
	      differ  significantly  from  the number of lines for macro-heavy
	      code. The	default	is 800.

       BranchThreshold
	      Flag functions exceeding this number of control statements.  The
	      default is -1 (ignore the	number of branches).

       ParameterThreshold
	      Flag functions that exceed a specified number of parameters. The
	      default is -1 (ignore the	number of parameters).

       NestingThreshold
	      Flag compound statements which create next nesting  level	 after
	      NestingThreshold.	 This  may  differ  significantly from the ex-
	      pected value for macro-heavy code. The default is	-1 (ignore the
	      nesting level).

       VariableThreshold
	      Flag  functions  exceeding  this number of variables declared in
	      the body.	 The default is	-1 (ignore the number  of  variables).
	      Please  note  that function parameters and variables declared in
	      lambdas, GNU Statement  Expressions,  and	 nested	 class	inline
	      functions	are not	counted.

   readability-identifier-naming
       Checks for identifiers naming style mismatch.

       This  check  will  try  to enforce coding guidelines on the identifiers
       naming. It supports one of the following	casing types and tries to con-
       vert from one to	another	if a mismatch is detected

       Casing types inclde:

	  o lower_case,

	  o UPPER_CASE,

	  o camelBack,

	  o CamelCase,

	  o camel_Snake_Back,

	  o Camel_Snake_Case,

	  o aNy_CasE.

       It  also	 supports  a fixed prefix and suffix that will be prepended or
       appended	to the identifiers, regardless of the casing.

       Many configuration options are available, in order to be	able to	create
       different  rules	 for  different	 kinds of identifiers. In general, the
       rules are falling back to a more	generic	rule if	the specific  case  is
       not configured.

   Options
       The following options are describe below:

	  o AbstractClassCase, AbstractClassPrefix, AbstractClassSuffix

	  o ClassCase, ClassPrefix, ClassSuffix

	  o ClassConstantCase, ClassConstantPrefix, ClassConstantSuffix

	  o ClassMemberCase, ClassMemberPrefix,	ClassMemberSuffix

	  o ClassMethodCase, ClassMethodPrefix,	ClassMethodSuffix

	  o ConstantCase, ConstantPrefix, ConstantSuffix

	  o ConstantMemberCase,	ConstantMemberPrefix, ConstantMemberSuffix

	  o ConstantParameterCase,		      ConstantParameterPrefix,
	    ConstantParameterSuffix

	  o ConstantPointerParameterCase,      ConstantPointerParameterPrefix,
	    ConstantPointerParameterSuffix

	  o ConstexprFunctionCase,		      ConstexprFunctionPrefix,
	    ConstexprFunctionSuffix

	  o ConstexprMethodCase, ConstexprMethodPrefix,	ConstexprMethodSuffix

	  o ConstexprVariableCase,		      ConstexprVariablePrefix,
	    ConstexprVariableSuffix

	  o EnumCase, EnumPrefix, EnumSuffix

	  o EnumConstantCase, EnumConstantPrefix, EnumConstantSuffix

	  o FunctionCase, FunctionPrefix, FunctionSuffix

	  o GlobalConstantCase,	GlobalConstantPrefix, GlobalConstantSuffix

	  o GlobalConstantPointerCase,		  GlobalConstantPointerPrefix,
	    GlobalConstantPointerSuffix

	  o GlobalFunctionCase,	GlobalFunctionPrefix, GlobalFunctionSuffix

	  o GlobalPointerCase, GlobalPointerPrefix, GlobalPointerSuffix

	  o GlobalVariableCase,	GlobalVariablePrefix, GlobalVariableSuffix

	  o InlineNamespaceCase, InlineNamespacePrefix,	InlineNamespaceSuffix

	  o LocalConstantCase, LocalConstantPrefix, LocalConstantSuffix

	  o LocalConstantPointerCase,		   LocalConstantPointerPrefix,
	    LocalConstantPointerSuffix

	  o LocalPointerCase, LocalPointerPrefix, LocalPointerSuffix

	  o LocalVariableCase, LocalVariablePrefix, LocalVariableSuffix

	  o MemberCase,	MemberPrefix, MemberSuffix

	  o MethodCase,	MethodPrefix, MethodSuffix

	  o NamespaceCase, NamespacePrefix, NamespaceSuffix

	  o ParameterCase, ParameterPrefix, ParameterSuffix

	  o ParameterPackCase, ParameterPackPrefix, ParameterPackSuffix

	  o PointerParameterCase,		       PointerParameterPrefix,
	    PointerParameterSuffix

	  o PrivateMemberCase, PrivateMemberPrefix, PrivateMemberSuffix

	  o PrivateMethodCase, PrivateMethodPrefix, PrivateMethodSuffix

	  o ProtectedMemberCase, ProtectedMemberPrefix,	ProtectedMemberSuffix

	  o ProtectedMethodCase, ProtectedMethodPrefix,	ProtectedMethodSuffix

	  o PublicMemberCase, PublicMemberPrefix, PublicMemberSuffix

	  o PublicMethodCase, PublicMethodPrefix, PublicMethodSuffix

	  o StaticConstantCase,	StaticConstantPrefix, StaticConstantSuffix

	  o StaticVariableCase,	StaticVariablePrefix, StaticVariableSuffix

	  o StructCase,	StructPrefix, StructSuffix

	  o TemplateParameterCase,		      TemplateParameterPrefix,
	    TemplateParameterSuffix

	  o TemplateTemplateParameterCase,    TemplateTemplateParameterPrefix,
	    TemplateTemplateParameterSuffix

	  o TypeAliasCase, TypeAliasPrefix, TypeAliasSuffix

	  o TypedefCase, TypedefPrefix,	TypedefSuffix

	  o TypeTemplateParameterCase,		  TypeTemplateParameterPrefix,
	    TypeTemplateParameterSuffix

	  o UnionCase, UnionPrefix, UnionSuffix

	  o ValueTemplateParameterCase,		 ValueTemplateParameterPrefix,
	    ValueTemplateParameterSuffix

	  o VariableCase, VariablePrefix, VariableSuffix

	  o VirtualMethodCase, VirtualMethodPrefix, VirtualMethodSuffix

       AbstractClassCase
	      When defined, the	check will ensure abstract class names conform
	      to the selected casing.

       AbstractClassPrefix
	      When  defined,  the  check will ensure abstract class names will
	      add the prefixed with the	given value (regardless	of casing).

       AbstractClassSuffix
	      When defined, the	check will ensure abstract  class  names  will
	      add the suffix with the given value (regardless of casing).

       For example using values	of:

	  o AbstractClassCase of lower_case

	  o AbstractClassPrefix	of pre_

	  o AbstractClassSuffix	of _post

       Identifies and/or transforms abstract class names as follows:

       Before:

	  class	ABSTRACT_CLASS {
	  public:
	    ABSTRACT_CLASS();
	  };

       After:

	  class	pre_abstract_class_post	{
	  public:
	    pre_abstract_class_post();
	  };

       ClassCase
	      When  defined,  the check	will ensure class names	conform	to the
	      selected casing.

       ClassPrefix
	      When defined, the	check will ensure class	 names	will  add  the
	      prefixed with the	given value (regardless	of casing).

       ClassSuffix
	      When  defined,  the  check  will ensure class names will add the
	      suffix with the given value (regardless of casing).

       For example using values	of:

	  o ClassCase of lower_case

	  o ClassPrefix	of pre_

	  o ClassSuffix	of _post

       Identifies and/or transforms class names	as follows:

       Before:

	  class	FOO {
	  public:
	    FOO();
	    ~FOO();
	  };

       After:

	  class	pre_foo_post {
	  public:
	    pre_foo_post();
	    ~pre_foo_post();
	  };

       ClassConstantCase
	      When defined, the	check will ensure class	constant names conform
	      to the selected casing.

       ClassConstantPrefix
	      When  defined,  the  check will ensure class constant names will
	      add the prefixed with the	given value (regardless	of casing).

       ClassConstantSuffix
	      When defined, the	check will ensure class	 constant  names  will
	      add the suffix with the given value (regardless of casing).

       For example using values	of:

	  o ClassConstantCase of lower_case

	  o ClassConstantPrefix	of pre_

	  o ClassConstantSuffix	of _post

       Identifies and/or transforms class constant names as follows:

       Before:

	  class	FOO {
	  public:
	    static const int CLASS_CONSTANT;
	  };

       After:

	  class	FOO {
	  public:
	    static const int pre_class_constant_post;
	  };

       ClassMemberCase
	      When  defined,  the check	will ensure class member names conform
	      to the selected casing.

       ClassMemberPrefix
	      When defined, the	check will ensure class	member names will  add
	      the prefixed with	the given value	(regardless of casing).

       ClassMemberSuffix
	      When  defined, the check will ensure class member	names will add
	      the suffix with the given	value (regardless of casing).

       For example using values	of:

	  o ClassMemberCase of lower_case

	  o ClassMemberPrefix of pre_

	  o ClassMemberSuffix of _post

       Identifies and/or transforms class member names as follows:

       Before:

	  class	FOO {
	  public:
	    static int CLASS_CONSTANT;
	  };

       After:

	  class	FOO {
	  public:
	    static int pre_class_constant_post;
	  };

       ClassMethodCase
	      When defined, the	check will ensure class	method	names  conform
	      to the selected casing.

       ClassMethodPrefix
	      When  defined, the check will ensure class method	names will add
	      the prefixed with	the given value	(regardless of casing).

       ClassMethodSuffix
	      When defined, the	check will ensure class	method names will  add
	      the suffix with the given	value (regardless of casing).

       For example using values	of:

	  o ClassMethodCase of lower_case

	  o ClassMethodPrefix of pre_

	  o ClassMethodSuffix of _post

       Identifies and/or transforms class method names as follows:

       Before:

	  class	FOO {
	  public:
	    int	CLASS_MEMBER();
	  };

       After:

	  class	FOO {
	  public:
	    int	pre_class_member_post();
	  };

       ConstantCase
	      When  defined,  the  check will ensure constant names conform to
	      the selected casing.

       ConstantPrefix
	      When defined, the	check will ensure constant names will add  the
	      prefixed with the	given value (regardless	of casing).

       ConstantSuffix
	      When  defined, the check will ensure constant names will add the
	      suffix with the given value (regardless of casing).

       For example using values	of:

	  o ConstantCase of lower_case

	  o ConstantPrefix of pre_

	  o ConstantSuffix of _post

       Identifies and/or transforms constant names as follows:

       Before:

	  void function() { unsigned const MyConst_array[] = {1, 2, 3};	}

       After:

	  void function() { unsigned const pre_myconst_array_post[] = {1, 2, 3}; }

       ConstantMemberCase
	      When defined, the	check will ensure constant member  names  con-
	      form to the selected casing.

       ConstantMemberPrefix
	      When  defined,  the check	will ensure constant member names will
	      add the prefixed with the	given value (regardless	of casing).

       ConstantMemberSuffix
	      When defined, the	check will ensure constant member  names  will
	      add the suffix with the given value (regardless of casing).

       For example using values	of:

	  o ConstantMemberCase of lower_case

	  o ConstantMemberPrefix of pre_

	  o ConstantMemberSuffix of _post

       Identifies and/or transforms constant member names as follows:

       Before:

	  class	Foo {
	    char const MY_ConstMember_string[4]	= "123";
	  }

       After:

	  class	Foo {
	    char const pre_my_constmember_string_post[4] = "123";
	  }

       ConstantParameterCase
	      When  defined,  the  check  will ensure constant parameter names
	      conform to the selected casing.

       ConstantParameterPrefix
	      When defined, the	check will  ensure  constant  parameter	 names
	      will  add	 the prefixed with the given value (regardless of cas-
	      ing).

       ConstantParameterSuffix
	      When defined, the	check will  ensure  constant  parameter	 names
	      will add the suffix with the given value (regardless of casing).

       For example using values	of:

	  o ConstantParameterCase of lower_case

	  o ConstantParameterPrefix of pre_

	  o ConstantParameterSuffix of _post

       Identifies and/or transforms constant parameter names as	follows:

       Before:

	  void GLOBAL_FUNCTION(int PARAMETER_1,	int const CONST_parameter);

       After:

	  void GLOBAL_FUNCTION(int PARAMETER_1,	int const pre_const_parameter_post);

       ConstantPointerParameterCase
	      When  defined,  the check	will ensure constant pointer parameter
	      names conform to the selected casing.

       ConstantPointerParameterPrefix
	      When defined, the	check will ensure constant  pointer  parameter
	      names  will add the prefixed with	the given value	(regardless of
	      casing).

       ConstantPointerParameterSuffix
	      When defined, the	check will ensure constant  pointer  parameter
	      names  will  add	the suffix with	the given value	(regardless of
	      casing).

       For example using values	of:

	  o ConstantPointerParameterCase of lower_case

	  o ConstantPointerParameterPrefix of pre_

	  o ConstantPointerParameterSuffix of _post

       Identifies and/or transforms constant pointer parameter names  as  fol-
       lows:

       Before:

	  void GLOBAL_FUNCTION(int const *CONST_parameter);

       After:

	  void GLOBAL_FUNCTION(int const *pre_const_parameter_post);

       ConstexprFunctionCase
	      When  defined,  the  check  will ensure constexpr	function names
	      conform to the selected casing.

       ConstexprFunctionPrefix
	      When defined, the	check will  ensure  constexpr  function	 names
	      will  add	 the prefixed with the given value (regardless of cas-
	      ing).

       ConstexprFunctionSuffix
	      When defined, the	check will  ensure  constexpr  function	 names
	      will add the suffix with the given value (regardless of casing).

       For example using values	of:

	  o ConstexprFunctionCase of lower_case

	  o ConstexprFunctionPrefix of pre_

	  o ConstexprFunctionSuffix of _post

       Identifies and/or transforms constexpr function names as	follows:

       Before:

	  constexpr int	CE_function() {	return 3; }

       After:

	  constexpr int	pre_ce_function_post() { return	3; }

       ConstexprMethodCase
	      When  defined, the check will ensure constexpr method names con-
	      form to the selected casing.

       ConstexprMethodPrefix
	      When defined, the	check will ensure constexpr method names  will
	      add the prefixed with the	given value (regardless	of casing).

       ConstexprMethodSuffix
	      When  defined, the check will ensure constexpr method names will
	      add the suffix with the given value (regardless of casing).

       For example using values	of:

	  o ConstexprMethodCase	of lower_case

	  o ConstexprMethodPrefix of pre_

	  o ConstexprMethodSuffix of _post

       Identifies and/or transforms constexpr method names as follows:

       Before:

	  class	Foo {
	  public:
	    constexpr int CST_expr_Method() { return 2;	}
	  }

       After:

	  class	Foo {
	  public:
	    constexpr int pre_cst_expr_method_post() { return 2; }
	  }

       ConstexprVariableCase
	      When defined, the	check will  ensure  constexpr  variable	 names
	      conform to the selected casing.

       ConstexprVariablePrefix
	      When  defined,  the  check  will ensure constexpr	variable names
	      will add the prefixed with the given value (regardless  of  cas-
	      ing).

       ConstexprVariableSuffix
	      When  defined,  the  check  will ensure constexpr	variable names
	      will add the suffix with the given value (regardless of casing).

       For example using values	of:

	  o ConstexprVariableCase of lower_case

	  o ConstexprVariablePrefix of pre_

	  o ConstexprVariableSuffix of _post

       Identifies and/or transforms constexpr variable names as	follows:

       Before:

	  constexpr int	ConstExpr_variable = MyConstant;

       After:

	  constexpr int	pre_constexpr_variable_post = MyConstant;

       EnumCase
	      When defined, the	check will ensure enumeration names conform to
	      the selected casing.

       EnumPrefix
	      When  defined,  the check	will ensure enumeration	names will add
	      the prefixed with	the given value	(regardless of casing).

       EnumSuffix
	      When defined, the	check will ensure enumeration names  will  add
	      the suffix with the given	value (regardless of casing).

       For example using values	of:

	  o EnumCase of	lower_case

	  o EnumPrefix of pre_

	  o EnumSuffix of _post

       Identifies and/or transforms enumeration	names as follows:

       Before:

	  enum FOO { One, Two, Three };

       After:

	  enum pre_foo_post { One, Two,	Three };

       EnumConstantCase
	      When  defined,  the check	will ensure enumeration	constant names
	      conform to the selected casing.

       EnumConstantPrefix
	      When defined, the	check will ensure enumeration  constant	 names
	      will  add	 the prefixed with the given value (regardless of cas-
	      ing).

       EnumConstantSuffix
	      When defined, the	check will ensure enumeration  constant	 names
	      will add the suffix with the given value (regardless of casing).

       For example using values	of:

	  o EnumConstantCase of	lower_case

	  o EnumConstantPrefix of pre_

	  o EnumConstantSuffix of _post

       Identifies and/or transforms enumeration	constant names as follows:

       Before:

	  enum FOO { One, Two, Three };

       After:

	  enum FOO { pre_One_post, pre_Two_post, pre_Three_post	};

       FunctionCase
	      When  defined,  the  check will ensure function names conform to
	      the selected casing.

       FunctionPrefix
	      When defined, the	check will ensure function names will add  the
	      prefixed with the	given value (regardless	of casing).

       FunctionSuffix
	      When  defined, the check will ensure function names will add the
	      suffix with the given value (regardless of casing).

       For example using values	of:

	  o FunctionCase of lower_case

	  o FunctionPrefix of pre_

	  o FunctionSuffix of _post

       Identifies and/or transforms function names as follows:

       Before:

	  char MY_Function_string();

       After:

	  char pre_my_function_string_post();

       GlobalConstantCase
	      When defined, the	check will ensure global constant  names  con-
	      form to the selected casing.

       GlobalConstantPrefix
	      When  defined,  the check	will ensure global constant names will
	      add the prefixed with the	given value (regardless	of casing).

       GlobalConstantSuffix
	      When defined, the	check will ensure global constant  names  will
	      add the suffix with the given value (regardless of casing).

       For example using values	of:

	  o GlobalConstantCase of lower_case

	  o GlobalConstantPrefix of pre_

	  o GlobalConstantSuffix of _post

       Identifies and/or transforms global constant names as follows:

       Before:

	  unsigned const MyConstGlobal_array[] = {1, 2,	3};

       After:

	  unsigned const pre_myconstglobal_array_post[]	= {1, 2, 3};

       GlobalConstantPointerCase
	      When  defined,  the  check  will	ensure global constant pointer
	      names conform to the selected casing.

       GlobalConstantPointerPrefix
	      When defined, the	check  will  ensure  global  constant  pointer
	      names  will add the prefixed with	the given value	(regardless of
	      casing).

       GlobalConstantPointerSuffix
	      When defined, the	check  will  ensure  global  constant  pointer
	      names  will  add	the suffix with	the given value	(regardless of
	      casing).

       For example using values	of:

	  o GlobalConstantPointerCase of lower_case

	  o GlobalConstantPointerPrefix	of pre_

	  o GlobalConstantPointerSuffix	of _post

       Identifies and/or transforms global constant pointer names as follows:

       Before:

	  int *const MyConstantGlobalPointer = nullptr;

       After:

	  int *const pre_myconstantglobalpointer_post =	nullptr;

       GlobalFunctionCase
	      When defined, the	check will ensure global function  names  con-
	      form to the selected casing.

       GlobalFunctionPrefix
	      When  defined,  the check	will ensure global function names will
	      add the prefixed with the	given value (regardless	of casing).

       GlobalFunctionSuffix
	      When defined, the	check will ensure global function  names  will
	      add the suffix with the given value (regardless of casing).

       For example using values	of:

	  o GlobalFunctionCase of lower_case

	  o GlobalFunctionPrefix of pre_

	  o GlobalFunctionSuffix of _post

       Identifies and/or transforms global function names as follows:

       Before:

	  void GLOBAL_FUNCTION(int PARAMETER_1,	int const CONST_parameter);

       After:

	  void pre_global_function_post(int PARAMETER_1, int const CONST_parameter);

       GlobalPointerCase
	      When defined, the	check will ensure global pointer names conform
	      to the selected casing.

       GlobalPointerPrefix
	      When defined, the	check will ensure global  pointer  names  will
	      add the prefixed with the	given value (regardless	of casing).

       GlobalPointerSuffix
	      When  defined,  the  check will ensure global pointer names will
	      add the suffix with the given value (regardless of casing).

       For example using values	of:

	  o GlobalPointerCase of lower_case

	  o GlobalPointerPrefix	of pre_

	  o GlobalPointerSuffix	of _post

       Identifies and/or transforms global pointer names as follows:

       Before:

	  int *GLOBAL3;

       After:

	  int *pre_global3_post;

       GlobalVariableCase
	      When defined, the	check will ensure global variable  names  con-
	      form to the selected casing.

       GlobalVariablePrefix
	      When  defined,  the check	will ensure global variable names will
	      add the prefixed with the	given value (regardless	of casing).

       GlobalVariableSuffix
	      When defined, the	check will ensure global variable  names  will
	      add the suffix with the given value (regardless of casing).

       For example using values	of:

	  o GlobalVariableCase of lower_case

	  o GlobalVariablePrefix of pre_

	  o GlobalVariableSuffix of _post

       Identifies and/or transforms global variable names as follows:

       Before:

	  int GLOBAL3;

       After:

	  int pre_global3_post;

       InlineNamespaceCase
	      When defined, the	check will ensure inline namespaces names con-
	      form to the selected casing.

       InlineNamespacePrefix
	      When defined, the	check will ensure inline namespaces names will
	      add the prefixed with the	given value (regardless	of casing).

       InlineNamespaceSuffix
	      When defined, the	check will ensure inline namespaces names will
	      add the suffix with the given value (regardless of casing).

       For example using values	of:

	  o InlineNamespaceCase	of lower_case

	  o InlineNamespacePrefix of pre_

	  o InlineNamespaceSuffix of _post

       Identifies and/or transforms inline namespaces names as follows:

       Before:

	  namespace FOO_NS {
	  inline namespace InlineNamespace {
	  ...
	  }
	  } // namespace FOO_NS

       After:

	  namespace FOO_NS {
	  inline namespace pre_inlinenamespace_post {
	  ...
	  }
	  } // namespace FOO_NS

       LocalConstantCase
	      When defined, the	check will ensure local	constant names conform
	      to the selected casing.

       LocalConstantPrefix
	      When  defined,  the  check will ensure local constant names will
	      add the prefixed with the	given value (regardless	of casing).

       LocalConstantSuffix
	      When defined, the	check will ensure local	 constant  names  will
	      add the suffix with the given value (regardless of casing).

       For example using values	of:

	  o LocalConstantCase of lower_case

	  o LocalConstantPrefix	of pre_

	  o LocalConstantSuffix	of _post

       Identifies and/or transforms local constant names as follows:

       Before:

	  void foo() { int const local_Constant	= 3; }

       After:

	  void foo() { int const pre_local_constant_post = 3; }

       LocalConstantPointerCase
	      When defined, the	check will ensure local	constant pointer names
	      conform to the selected casing.

       LocalConstantPointerPrefix
	      When defined, the	check will ensure local	constant pointer names
	      will  add	 the prefixed with the given value (regardless of cas-
	      ing).

       LocalConstantPointerSuffix
	      When defined, the	check will ensure local	constant pointer names
	      will add the suffix with the given value (regardless of casing).

       For example using values	of:

	  o LocalConstantPointerCase of	lower_case

	  o LocalConstantPointerPrefix of pre_

	  o LocalConstantPointerSuffix of _post

       Identifies and/or transforms local constant pointer names as follows:

       Before:

	  void foo() { int const *local_Constant = 3; }

       After:

	  void foo() { int const *pre_local_constant_post = 3; }

       LocalPointerCase
	      When  defined, the check will ensure local pointer names conform
	      to the selected casing.

       LocalPointerPrefix
	      When defined, the	check will ensure local	pointer	names will add
	      the prefixed with	the given value	(regardless of casing).

       LocalPointerSuffix
	      When defined, the	check will ensure local	pointer	names will add
	      the suffix with the given	value (regardless of casing).

       For example using values	of:

	  o LocalPointerCase of	lower_case

	  o LocalPointerPrefix of pre_

	  o LocalPointerSuffix of _post

       Identifies and/or transforms local pointer names	as follows:

       Before:

	  void foo() { int *local_Constant; }

       After:

	  void foo() { int *pre_local_constant_post; }

       LocalVariableCase
	      When defined, the	check will ensure local	variable names conform
	      to the selected casing.

       LocalVariablePrefix
	      When  defined,  the  check will ensure local variable names will
	      add the prefixed with the	given value (regardless	of casing).

       LocalVariableSuffix
	      When defined, the	check will ensure local	 variable  names  will
	      add the suffix with the given value (regardless of casing).

       For example using values	of:

	  o LocalVariableCase of lower_case

	  o LocalVariablePrefix	of pre_

	  o LocalVariableSuffix	of _post

       Identifies and/or transforms local variable names as follows:

       Before:

	  void foo() { int local_Constant; }

       After:

	  void foo() { int pre_local_constant_post; }

       MemberCase
	      When  defined, the check will ensure member names	conform	to the
	      selected casing.

       MemberPrefix
	      When defined, the	check will ensure member names	will  add  the
	      prefixed with the	given value (regardless	of casing).

       MemberSuffix
	      When  defined,  the  check will ensure member names will add the
	      suffix with the given value (regardless of casing).

       For example using values	of:

	  o MemberCase of lower_case

	  o MemberPrefix of pre_

	  o MemberSuffix of _post

       Identifies and/or transforms member names as follows:

       Before:

	  class	Foo {
	    char MY_ConstMember_string[4];
	  }

       After:

	  class	Foo {
	    char pre_my_constmember_string_post[4];
	  }

       MethodCase
	      When defined, the	check will ensure method names conform to  the
	      selected casing.

       MethodPrefix
	      When  defined,  the  check will ensure method names will add the
	      prefixed with the	given value (regardless	of casing).

       MethodSuffix
	      When defined, the	check will ensure method names	will  add  the
	      suffix with the given value (regardless of casing).

       For example using values	of:

	  o MethodCase of lower_case

	  o MethodPrefix of pre_

	  o MethodSuffix of _post

       Identifies and/or transforms method names as follows:

       Before:

	  class	Foo {
	    char MY_Method_string();
	  }

       After:

	  class	Foo {
	    char pre_my_method_string_post();
	  }

       NamespaceCase
	      When  defined,  the check	will ensure namespace names conform to
	      the selected casing.

       NamespacePrefix
	      When defined, the	check will ensure namespace names will add the
	      prefixed with the	given value (regardless	of casing).

       NamespaceSuffix
	      When defined, the	check will ensure namespace names will add the
	      suffix with the given value (regardless of casing).

       For example using values	of:

	  o NamespaceCase of lower_case

	  o NamespacePrefix of pre_

	  o NamespaceSuffix of _post

       Identifies and/or transforms namespace names as follows:

       Before:

	  namespace FOO_NS {
	  ...
	  }

       After:

	  namespace pre_foo_ns_post {
	  ...
	  }

       ParameterCase
	      When defined, the	check will ensure parameter names  conform  to
	      the selected casing.

       ParameterPrefix
	      When defined, the	check will ensure parameter names will add the
	      prefixed with the	given value (regardless	of casing).

       ParameterSuffix
	      When defined, the	check will ensure parameter names will add the
	      suffix with the given value (regardless of casing).

       For example using values	of:

	  o ParameterCase of lower_case

	  o ParameterPrefix of pre_

	  o ParameterSuffix of _post

       Identifies and/or transforms parameter names as follows:

       Before:

	  void GLOBAL_FUNCTION(int PARAMETER_1,	int const CONST_parameter);

       After:

	  void GLOBAL_FUNCTION(int pre_parameter_post, int const CONST_parameter);

       ParameterPackCase
	      When defined, the	check will ensure parameter pack names conform
	      to the selected casing.

       ParameterPackPrefix
	      When defined, the	check will ensure parameter  pack  names  will
	      add the prefixed with the	given value (regardless	of casing).

       ParameterPackSuffix
	      When  defined,  the  check will ensure parameter pack names will
	      add the suffix with the given value (regardless of casing).

       For example using values	of:

	  o ParameterPackCase of lower_case

	  o ParameterPackPrefix	of pre_

	  o ParameterPackSuffix	of _post

       Identifies and/or transforms parameter pack names as follows:

       Before:

	  template <typename...	TYPE_parameters> {
	    void FUNCTION(int... TYPE_parameters);
	  }

       After:

	  template <typename...	TYPE_parameters> {
	    void FUNCTION(int... pre_type_parameters_post);
	  }

       PointerParameterCase
	      When defined, the	check will ensure pointer parameter names con-
	      form to the selected casing.

       PointerParameterPrefix
	      When defined, the	check will ensure pointer parameter names will
	      add the prefixed with the	given value (regardless	of casing).

       PointerParameterSuffix
	      When defined, the	check will ensure pointer parameter names will
	      add the suffix with the given value (regardless of casing).

       For example using values	of:

	  o PointerParameterCase of lower_case

	  o PointerParameterPrefix of pre_

	  o PointerParameterSuffix of _post

       Identifies and/or transforms pointer parameter names as follows:

       Before:

	  void FUNCTION(int *PARAMETER);

       After:

	  void FUNCTION(int *pre_parameter_post);

       PrivateMemberCase
	      When defined, the	check will ensure private member names conform
	      to the selected casing.

       PrivateMemberPrefix
	      When defined, the	check will ensure private  member  names  will
	      add the prefixed with the	given value (regardless	of casing).

       PrivateMemberSuffix
	      When  defined,  the  check will ensure private member names will
	      add the suffix with the given value (regardless of casing).

       For example using values	of:

	  o PrivateMemberCase of lower_case

	  o PrivateMemberPrefix	of pre_

	  o PrivateMemberSuffix	of _post

       Identifies and/or transforms private member names as follows:

       Before:

	  class	Foo {
	  private:
	    int	Member_Variable;
	  }

       After:

	  class	Foo {
	  private:
	    int	pre_member_variable_post;
	  }

       PrivateMethodCase
	      When defined, the	check will ensure private method names conform
	      to the selected casing.

       PrivateMethodPrefix
	      When  defined,  the  check will ensure private method names will
	      add the prefixed with the	given value (regardless	of casing).

       PrivateMethodSuffix
	      When defined, the	check will ensure private  method  names  will
	      add the suffix with the given value (regardless of casing).

       For example using values	of:

	  o PrivateMethodCase of lower_case

	  o PrivateMethodPrefix	of pre_

	  o PrivateMethodSuffix	of _post

       Identifies and/or transforms private method names as follows:

       Before:

	  class	Foo {
	  private:
	    int	Member_Method();
	  }

       After:

	  class	Foo {
	  private:
	    int	pre_member_method_post();
	  }

       ProtectedMemberCase
	      When  defined, the check will ensure protected member names con-
	      form to the selected casing.

       ProtectedMemberPrefix
	      When defined, the	check will ensure protected member names  will
	      add the prefixed with the	given value (regardless	of casing).

       ProtectedMemberSuffix
	      When  defined, the check will ensure protected member names will
	      add the suffix with the given value (regardless of casing).

       For example using values	of:

	  o ProtectedMemberCase	of lower_case

	  o ProtectedMemberPrefix of pre_

	  o ProtectedMemberSuffix of _post

       Identifies and/or transforms protected member names as follows:

       Before:

	  class	Foo {
	  protected:
	    int	Member_Variable;
	  }

       After:

	  class	Foo {
	  protected:
	    int	pre_member_variable_post;
	  }

       ProtectedMethodCase
	      When defined, the	check will ensure protect method names conform
	      to the selected casing.

       ProtectedMethodPrefix
	      When  defined,  the  check will ensure protect method names will
	      add the prefixed with the	given value (regardless	of casing).

       ProtectedMethodSuffix
	      When defined, the	check will ensure protect  method  names  will
	      add the suffix with the given value (regardless of casing).

       For example using values	of:

	  o ProtectedMethodCase	of lower_case

	  o ProtectedMethodPrefix of pre_

	  o ProtectedMethodSuffix of _post

       Identifies and/or transforms protect method names as follows:

       Before:

	  class	Foo {
	  protected:
	    int	Member_Method();
	  }

       After:

	  class	Foo {
	  protected:
	    int	pre_member_method_post();
	  }

       PublicMemberCase
	      When  defined, the check will ensure public member names conform
	      to the selected casing.

       PublicMemberPrefix
	      When defined, the	check will ensure public member	names will add
	      the prefixed with	the given value	(regardless of casing).

       PublicMemberSuffix
	      When defined, the	check will ensure public member	names will add
	      the suffix with the given	value (regardless of casing).

       For example using values	of:

	  o PublicMemberCase of	lower_case

	  o PublicMemberPrefix of pre_

	  o PublicMemberSuffix of _post

       Identifies and/or transforms public member names	as follows:

       Before:

	  class	Foo {
	  public:
	    int	Member_Variable;
	  }

       After:

	  class	Foo {
	  public:
	    int	pre_member_variable_post;
	  }

       PublicMethodCase
	      When defined, the	check will ensure public method	names  conform
	      to the selected casing.

       PublicMethodPrefix
	      When defined, the	check will ensure public method	names will add
	      the prefixed with	the given value	(regardless of casing).

       PublicMethodSuffix
	      When defined, the	check will ensure public method	names will add
	      the suffix with the given	value (regardless of casing).

       For example using values	of:

	  o PublicMethodCase of	lower_case

	  o PublicMethodPrefix of pre_

	  o PublicMethodSuffix of _post

       Identifies and/or transforms public method names	as follows:

       Before:

	  class	Foo {
	  public:
	    int	Member_Method();
	  }

       After:

	  class	Foo {
	  public:
	    int	pre_member_method_post();
	  }

       StaticConstantCase
	      When  defined,  the check	will ensure static constant names con-
	      form to the selected casing.

       StaticConstantPrefix
	      When defined, the	check will ensure static constant  names  will
	      add the prefixed with the	given value (regardless	of casing).

       StaticConstantSuffix
	      When  defined,  the check	will ensure static constant names will
	      add the suffix with the given value (regardless of casing).

       For example using values	of:

	  o StaticConstantCase of lower_case

	  o StaticConstantPrefix of pre_

	  o StaticConstantSuffix of _post

       Identifies and/or transforms static constant names as follows:

       Before:

	  static unsigned const	MyConstStatic_array[] =	{1, 2, 3};

       After:

	  static unsigned const	pre_myconststatic_array_post[] = {1, 2,	3};

       StaticVariableCase
	      When defined, the	check will ensure static variable  names  con-
	      form to the selected casing.

       StaticVariablePrefix
	      When  defined,  the check	will ensure static variable names will
	      add the prefixed with the	given value (regardless	of casing).

       StaticVariableSuffix
	      When defined, the	check will ensure static variable  names  will
	      add the suffix with the given value (regardless of casing).

       For example using values	of:

	  o StaticVariableCase of lower_case

	  o StaticVariablePrefix of pre_

	  o StaticVariableSuffix of _post

       Identifies and/or transforms static variable names as follows:

       Before:

	  static unsigned MyStatic_array[] = {1, 2, 3};

       After:

	  static unsigned pre_mystatic_array_post[] = {1, 2, 3};

       StructCase
	      When  defined, the check will ensure struct names	conform	to the
	      selected casing.

       StructPrefix
	      When defined, the	check will ensure struct names	will  add  the
	      prefixed with the	given value (regardless	of casing).

       StructSuffix
	      When  defined,  the  check will ensure struct names will add the
	      suffix with the given value (regardless of casing).

       For example using values	of:

	  o StructCase of lower_case

	  o StructPrefix of pre_

	  o StructSuffix of _post

       Identifies and/or transforms struct names as follows:

       Before:

	  struct FOO {
	    FOO();
	    ~FOO();
	  };

       After:

	  struct pre_foo_post {
	    pre_foo_post();
	    ~pre_foo_post();
	  };

       TemplateParameterCase
	      When defined, the	check will  ensure  template  parameter	 names
	      conform to the selected casing.

       TemplateParameterPrefix
	      When  defined,  the  check  will ensure template parameter names
	      will add the prefixed with the given value (regardless  of  cas-
	      ing).

       TemplateParameterSuffix
	      When  defined,  the  check  will ensure template parameter names
	      will add the suffix with the given value (regardless of casing).

       For example using values	of:

	  o TemplateParameterCase of lower_case

	  o TemplateParameterPrefix of pre_

	  o TemplateParameterSuffix of _post

       Identifies and/or transforms template parameter names as	follows:

       Before:

	  template <typename T>	class Foo {};

       After:

	  template <typename pre_t_post> class Foo {};

       TemplateTemplateParameterCase
	      When defined, the	check will ensure template template  parameter
	      names conform to the selected casing.

       TemplateTemplateParameterPrefix
	      When  defined, the check will ensure template template parameter
	      names will add the prefixed with the given value (regardless  of
	      casing).

       TemplateTemplateParameterSuffix
	      When  defined, the check will ensure template template parameter
	      names will add the suffix	with the given	value  (regardless  of
	      casing).

       For example using values	of:

	  o TemplateTemplateParameterCase of lower_case

	  o TemplateTemplateParameterPrefix of pre_

	  o TemplateTemplateParameterSuffix of _post

       Identifies  and/or transforms template template parameter names as fol-
       lows:

       Before:

	  template <template <typename>	class TPL_parameter, int COUNT_params,
		    typename...	TYPE_parameters>

       After:

	  template <template <typename>	class pre_tpl_parameter_post, int COUNT_params,
		    typename...	TYPE_parameters>

       TypeAliasCase
	      When defined, the	check will ensure type alias names conform  to
	      the selected casing.

       TypeAliasPrefix
	      When  defined,  the  check will ensure type alias	names will add
	      the prefixed with	the given value	(regardless of casing).

       TypeAliasSuffix
	      When defined, the	check will ensure type alias  names  will  add
	      the suffix with the given	value (regardless of casing).

       For example using values	of:

	  o TypeAliasCase of lower_case

	  o TypeAliasPrefix of pre_

	  o TypeAliasSuffix of _post

       Identifies and/or transforms type alias names as	follows:

       Before:

	  using	MY_STRUCT_TYPE = my_structure;

       After:

	  using	pre_my_struct_type_post	= my_structure;

       TypedefCase
	      When defined, the	check will ensure typedef names	conform	to the
	      selected casing.

       TypedefPrefix
	      When defined, the	check will ensure typedef names	will  add  the
	      prefixed with the	given value (regardless	of casing).

       TypedefSuffix
	      When  defined,  the check	will ensure typedef names will add the
	      suffix with the given value (regardless of casing).

       For example using values	of:

	  o TypedefCase	of lower_case

	  o TypedefPrefix of pre_

	  o TypedefSuffix of _post

       Identifies and/or transforms typedef names as follows:

       Before:

	  typedef int MYINT;

       After:

	  typedef int pre_myint_post;

       TypeTemplateParameterCase
	      When defined, the	check  will  ensure  type  template  parameter
	      names conform to the selected casing.

       TypeTemplateParameterPrefix
	      When  defined,  the  check  will	ensure type template parameter
	      names will add the prefixed with the given value (regardless  of
	      casing).

       TypeTemplateParameterSuffix
	      When  defined,  the  check  will	ensure type template parameter
	      names will add the suffix	with the given	value  (regardless  of
	      casing).

       For example using values	of:

	  o TypeTemplateParameterCase of lower_case

	  o TypeTemplateParameterPrefix	of pre_

	  o TypeTemplateParameterSuffix	of _post

       Identifies and/or transforms type template parameter names as follows:

       Before:

	  template <template <typename>	class TPL_parameter, int COUNT_params,
		    typename...	TYPE_parameters>

       After:

	  template <template <typename>	class TPL_parameter, int COUNT_params,
		    typename...	pre_type_parameters_post>

       UnionCase
	      When  defined,  the check	will ensure union names	conform	to the
	      selected casing.

       UnionPrefix
	      When defined, the	check will ensure union	 names	will  add  the
	      prefixed with the	given value (regardless	of casing).

       UnionSuffix
	      When  defined,  the  check  will ensure union names will add the
	      suffix with the given value (regardless of casing).

       For example using values	of:

	  o UnionCase of lower_case

	  o UnionPrefix	of pre_

	  o UnionSuffix	of _post

       Identifies and/or transforms union names	as follows:

       Before:

	  union	FOO {
	    int	a;
	    char b;
	  };

       After:

	  union	pre_foo_post {
	    int	a;
	    char b;
	  };

       ValueTemplateParameterCase
	      When defined, the	check will  ensure  value  template  parameter
	      names conform to the selected casing.

       ValueTemplateParameterPrefix
	      When  defined,  the  check  will ensure value template parameter
	      names will add the prefixed with the given value (regardless  of
	      casing).

       ValueTemplateParameterSuffix
	      When  defined,  the  check  will ensure value template parameter
	      names will add the suffix	with the given	value  (regardless  of
	      casing).

       For example using values	of:

	  o ValueTemplateParameterCase of lower_case

	  o ValueTemplateParameterPrefix of pre_

	  o ValueTemplateParameterSuffix of _post

       Identifies and/or transforms value template parameter names as follows:

       Before:

	  template <template <typename>	class TPL_parameter, int COUNT_params,
		    typename...	TYPE_parameters>

       After:

	  template <template <typename>	class TPL_parameter, int pre_count_params_post,
		    typename...	TYPE_parameters>

       VariableCase
	      When  defined,  the  check will ensure variable names conform to
	      the selected casing.

       VariablePrefix
	      When defined, the	check will ensure variable names will add  the
	      prefixed with the	given value (regardless	of casing).

       VariableSuffix
	      When  defined, the check will ensure variable names will add the
	      suffix with the given value (regardless of casing).

       For example using values	of:

	  o VariableCase of lower_case

	  o VariablePrefix of pre_

	  o VariableSuffix of _post

       Identifies and/or transforms variable names as follows:

       Before:

	  unsigned MyVariable;

       After:

	  unsigned pre_myvariable_post;

       VirtualMethodCase
	      When defined, the	check will ensure virtual method names conform
	      to the selected casing.

       VirtualMethodPrefix
	      When  defined,  the  check will ensure virtual method names will
	      add the prefixed with the	given value (regardless	of casing).

       VirtualMethodSuffix
	      When defined, the	check will ensure virtual  method  names  will
	      add the suffix with the given value (regardless of casing).

       For example using values	of:

	  o VirtualMethodCase of lower_case

	  o VirtualMethodPrefix	of pre_

	  o VirtualMethodSuffix	of _post

       Identifies and/or transforms virtual method names as follows:

       Before:

	  class	Foo {
	  public:
	    virtual int	MemberFunction();
	  }

       After:

	  class	Foo {
	  public:
	    virtual int	pre_member_function_post();
	  }

   readability-implicit-bool-conversion
       This  check  can	 be used to find implicit conversions between built-in
       types and booleans. Depending on	use case,  it  may  simply  help  with
       readability  of	the  code,  or	in some	cases, point to	potential bugs
       which remain unnoticed due to implicit conversions.

       The following is	a real-world example of	bug which  was	hiding	behind
       implicit	bool conversion:

	  class	Foo {
	    int	m_foo;

	  public:
	    void setFoo(bool foo) { m_foo = foo; } // warning: implicit	conversion bool	-> int
	    int	getFoo() { return m_foo; }
	  };

	  void use(Foo&	foo) {
	    bool value = foo.getFoo(); // warning: implicit conversion int -> bool
	  }

       This  code  is  the  result  of unsuccessful refactoring, where type of
       m_foo changed from bool to int. The programmer forgot to	change all oc-
       currences  of bool, and the remaining code is no	longer correct,	yet it
       still compiles without any visible warnings.

       In addition to issuing warnings,	fix-it	hints  are  provided  to  help
       solve  the  reported issues. This can be	used for improving readability
       of code,	for example:

	  void conversionsToBool() {
	    float floating;
	    bool boolean = floating;
	    // ^ propose replacement: bool boolean = floating != 0.0f;

	    int	integer;
	    if (integer) {}
	    // ^ propose replacement: if (integer != 0)	{}

	    int* pointer;
	    if (!pointer) {}
	    // ^ propose replacement: if (pointer == nullptr) {}

	    while (1) {}
	    // ^ propose replacement: while (true) {}
	  }

	  void functionTakingInt(int param);

	  void conversionsFromBool() {
	    bool boolean;
	    functionTakingInt(boolean);
	    // ^ propose replacement: functionTakingInt(static_cast<int>(boolean));

	    functionTakingInt(true);
	    // ^ propose replacement: functionTakingInt(1);
	  }

       In general, the following conversion types are checked:

       o integer expression/literal to boolean (conversion from	a  single  bit
	 bitfield to boolean is	explicitly allowed, since there's no ambiguity
	 / information loss in this case),

       o floating expression/literal to	boolean,

       o pointer/pointer to member/nullptr/NULL	to boolean,

       o boolean expression/literal to integer (conversion from	boolean	 to  a
	 single	bit bitfield is	explicitly allowed),

       o boolean expression/literal to floating.

       The rules for generating	fix-it hints are:

       o in  case of conversions from other built-in type to bool, an explicit
	 comparison is proposed	to make	it clear what exaclty  is  being  com-
	 pared:

	 o bool	 boolean  = floating; is changed to bool boolean = floating ==
	   0.0f;,

	 o for other types, appropriate	literals are used (0, 0u,  0.0f,  0.0,
	   nullptr),

       o in  case  of negated expressions conversion to	bool, the proposed re-
	 placement with	comparison is simplified:

	 o if (!pointer) is changed to if (pointer == nullptr),

       o in case of conversions	from bool to other built-in types, an explicit
	 static_cast  is proposed to make it clear that	a conversion is	taking
	 place:

	 o int	integer	  =   boolean;	 is   changed	to   int   integer   =
	   static_cast<int>(boolean);,

       o if  the  conversion is	performed on type literals, an equivalent lit-
	 eral is proposed, according to	what type is  actually	expected,  for
	 example:

	 o functionTakingBool(0); is changed to	functionTakingBool(false);,

	 o functionTakingInt(true); is changed to functionTakingInt(1);,

	 o for	other types, appropriate literals are used (false, true, 0, 1,
	   0u, 1u, 0.0f, 1.0f, 0.0, 1.0f).

       Some additional accommodations are made for pre-C++11 dialects:

       o false literal conversion to pointer is	detected,

       o instead of nullptr literal, 0 is proposed as replacement.

       Occurrences of implicit conversions inside macros and template  instan-
       tiations	 are deliberately ignored, as it is not	clear how to deal with
       such cases.

   Options
       AllowIntegerConditions
	      When non-zero, the check will allow conditional integer  conver-
	      sions. Default is	0.

       AllowPointerConditions
	      When  non-zero, the check	will allow conditional pointer conver-
	      sions. Default is	0.

   readability-inconsistent-declaration-parameter-name
       Find function declarations which	differ in parameter names.

       Example:

	  // in	foo.hpp:
	  void foo(int a, int b, int c);

	  // in	foo.cpp:
	  void foo(int d, int e, int f); // warning

       This check should help to enforce consistency in	large projects,	 where
       it  often happens that a	definition of function is refactored, changing
       the parameter names, but	its declaration	in header file is not updated.
       With  this  check, we can easily	find and correct such inconsistencies,
       keeping declaration and definition always in sync.

       Unnamed parameters are allowed and are not taken	into account when com-
       paring function declarations, for example:

	  void foo(int a);
	  void foo(int); // no warning

       One  name is also allowed to be a case-insensitive prefix/suffix	of the
       other:

	  void foo(int count);
	  void foo(int count_input) { // no warning
	    int	count =	adjustCount(count_input);
	  }

       To help with refactoring, in some cases fix-it hints are	 generated  to
       align  parameter	 names	to a single naming convention. This works with
       the assumption that the function	definition is the most up-to-date ver-
       sion, as	it directly references parameter names in its body. Example:

	  void foo(int a); // warning and fix-it hint (replace "a" to "b")
	  int foo(int b) { return b + 2; } // definition with use of "b"

       In the case of multiple redeclarations or function template specializa-
       tions, a	warning	is issued for every  redeclaration  or	specialization
       inconsistent  with  the	definition  or the first declaration seen in a
       translation unit.

       IgnoreMacros
	      If this option is	set to non-zero	(default is 1),	the check will
	      not warn about names declared inside macros.

       Strict If  this	option	is  set	to non-zero (default is	0), then names
	      must match exactly (or be	absent).

   readability-isolate-declaration
       Detects local variable declarations declaring more  than	 one  variable
       and tries to refactor the code to one statement per declaration.

       The  automatic code-transformation will use the same indentation	as the
       original	for every created statement and	add a line  break  after  each
       statement.  It keeps the	order of the variable declarations consistent,
       too.

	  void f() {
	    int	* pointer = nullptr, value = 42, * const const_ptr = &value;
	    // This declaration	will be	diagnosed and transformed into:
	    // int * pointer = nullptr;
	    // int value = 42;
	    // int * const const_ptr = &value;
	  }

       The check excludes places where it is necessary or  common  to  declare
       multiple	variables in one statement and there is	no other way supported
       in the language.	Please note that structured bindings are  not  consid-
       ered.

	  // It	is not possible	to transform this declaration and doing	the declaration
	  // before the	loop will increase the scope of	the variable 'Begin' and 'End'
	  // which is undesirable.
	  for (int Begin = 0, End = 100; Begin < End; ++Begin);
	  if (int Begin	= 42, Result = some_function(Begin); Begin == Result);

	  // It	is not possible	to transform this declaration because the result is
	  // not functionality preserving as 'j' and 'k' would not be part of the
	  // 'if' statement anymore.
	  if (SomeCondition())
	    int	i = 42,	j = 43,	k = function(i,j);

   Limitations
       Global variables	and member variables are excluded.

       The  check  currently  does not support the automatic transformation of
       member-pointer-types.

	  struct S {
	    int	a;
	    const int b;
	    void f() {}
	  };

	  void f() {
	    // Only a diagnostic message is emitted
	    int	S::*p =	&S::a, S::*const q = &S::a;
	  }

       Furthermore, the	transformation is very cautious	when it	detects	 vari-
       ous  kinds  of  macros  or  preprocessor	directives in the range	of the
       statement. In this case the transformation will not happen to avoid un-
       expected	side-effects due to macros.

	  #define NULL 0
	  #define MY_NICE_TYPE int **
	  #define VAR_NAME(name) name##__LINE__
	  #define A_BUNCH_OF_VARIABLES int m1 =	42, m2 = 43, m3	= 44;

	  void macros()	{
	    int	*p1 = NULL, *p2	= NULL;
	    // Will be transformed to
	    // int *p1 = NULL;
	    // int *p2 = NULL;

	    MY_NICE_TYPE p3, v1, v2;
	    // Won't be	transformed, but a diagnostic is emitted.

	    int	VAR_NAME(v3),
		VAR_NAME(v4),
		VAR_NAME(v5);
	    // Won't be	transformed, but a diagnostic is emitted.

	    A_BUNCH_OF_VARIABLES
	    // Won't be	transformed, but a diagnostic is emitted.

	    int	Unconditional,
	  #if CONFIGURATION
		IfConfigured = 42,
	  #else
		IfConfigured = 0;
	  #endif
	    // Won't be	transformed, but a diagnostic is emitted.
	  }

   readability-magic-numbers
       Detects	magic numbers, integer or floating point literals that are em-
       bedded in code and not introduced via constants or symbols.

       Many coding guidelines advise replacing the magic values	with  symbolic
       constants to improve readability. Here are a few	references:

	  o Rule ES.45:	Avoid _amagic constants_a; use symbolic constants	in C++
	    Core Guidelines

	  o Rule 5.1.1 Use symbolic names instead of literal values in code in
	    High Integrity C++

	  o Item  17  in "C++ Coding Standards:	101 Rules, Guidelines and Best
	    Practices" by Herb Sutter and Andrei Alexandrescu

	  o Chapter 17 in "Clean Code -	A handbook of agile  software  crafts-
	    manship."  by Robert C. Martin

	  o Rule  20701	 in  "TRAIN  REAL  TIME	DATA PROTOCOL Coding Rules" by
	    Armin-Hagen	Weiss, Bombardier

	  o http://wiki.c2.com/?MagicNumber

       Examples	of magic values:

	  double circleArea = 3.1415926535 * radius * radius;

	  double totalCharge = 1.08 * itemPrice;

	  int getAnswer() {
	     return -3;	// FILENOTFOUND
	  }

	  for (int mm =	1; mm <= 12; ++mm) {
	     std::cout << month[mm] << '\n';
	  }

       Example with magic values refactored:

	  double circleArea = M_PI * radius * radius;

	  const	double TAX_RATE	= 0.08;	 // or make it variable	and read from a	file

	  double totalCharge = (1.0 + TAX_RATE)	* itemPrice;

	  int getAnswer() {
	     return E_FILE_NOT_FOUND;
	  }

	  for (int mm =	1; mm <= MONTHS_IN_A_YEAR; ++mm) {
	     std::cout << month[mm] << '\n';
	  }

       For integral literals by	default	only 0 and 1 (and -1)  integer	values
       are  accepted  without  a  warning.  This  can  be  overridden with the
       IgnoredIntegerValues option. Negative values are	accepted if their  ab-
       solute value is present in the IgnoredIntegerValues list.

       As  a  special  case  for integral values, all powers of	two can	be ac-
       cepted without warning by enabling the IgnorePowersOf2IntegerValues op-
       tion.

       For  floating point literals by default the 0.0 floating	point value is
       accepted	without	a warning. The set of ignored floating point  literals
       can  be	configured  using  the IgnoredFloatingPointValues option.  For
       each value in that set, the given string	value is converted to a	float-
       ing-point  value	 representation	 used by the target architecture. If a
       floating-point literal value compares equal to  one  of	the  converted
       values,	then  that  literal  is	 not  diagnosed	by this	check. Because
       floating-point equality is used to determine  whether  to  diagnose  or
       not, the	user needs to be aware of the details of floating-point	repre-
       sentations for any values that  cannot  be  precisely  represented  for
       their target architecture.

       For  each  value	 in  the IgnoredFloatingPointValues set, both the sin-
       gle-precision form and double-precision form are	accepted (for example,
       if 3.14 is in the set, neither 3.14f nor	3.14 will produce a warning).

       Scientific notation is supported	for both source	code input and option.
       Alternatively, the check	for the	floating point numbers can be disabled
       for     all     floating	    point     values	 by    enabling	   the
       IgnoreAllFloatingPointValues option.

       Since values 0 and 0.0 are so common as the base	counter	of  loops,  or
       initialization  values for sums,	they are always	accepted without warn-
       ing, even if not	present	in the respective ignored values list.

   Options
       IgnoredIntegerValues
	      Semicolon-separated list of magic	positive integers that will be
	      accepted without a warning. Default values are {1, 2, 3, 4}, and
	      0	is accepted unconditionally.

       IgnorePowersOf2IntegerValues
	      Boolean value indicating whether to accept all powers-of-two in-
	      teger values without warning. Default value is false.

       IgnoredFloatingPointValues
	      Semicolon-separated list of magic	positive floating point	values
	      that will	be accepted without  a	warning.  Default  values  are
	      {1.0, 100.0} and 0.0 is accepted unconditionally.

       IgnoreAllFloatingPointValues
	      Boolean  value  indicating  whether to accept all	floating point
	      values without warning. Default value is false.

   readability-misleading-indentation
       Correct indentation helps to understand code. Mismatch of the syntacti-
       cal  structure  and  the	indentation of the code	may hide serious prob-
       lems.  Missing braces can also make it significantly harder to read the
       code, therefore it is important to use braces.

       The  way	to avoid dangling else is to always check that an else belongs
       to the if that begins in	the same column.

       You can omit braces when	your inner part	of e.g.	an  if	statement  has
       only  one  statement  in	it. Although in	that case you should begin the
       next statement in the same column with the if.

       Examples:

	  // Dangling else:
	  if (cond1)
	    if (cond2)
	      foo1();
	  else
	    foo2();  //	Wrong indentation: else	belongs	to if(cond2) statement.

	  // Missing braces:
	  if (cond1)
	    foo1();
	    foo2();  //	Not guarded by if(cond1).

   Limitations
       Note that this check only works as expected when	the tabs or spaces are
       used consistently and not mixed.

   readability-misplaced-array-index
       This check warns	for unusual array index	syntax.

       The following code has unusual array index syntax:

	  void f(int *X, int Y)	{
	    Y[X] = 0;
	  }

       becomes

	  void f(int *X, int Y)	{
	    X[Y] = 0;
	  }

       The check warns about such unusual syntax for readability reasons:

	      o	There  are programmers that are	not familiar with this unusual
		syntax.

	      o	It is possible that variables are mixed	up.

   readability-named-parameter
       Find functions with unnamed arguments.

       The check implements the	following rule originating in the  Google  C++
       Style Guide:

       https://google.github.io/styleguide/cppguide.html#Function_Declarations_and_Definitions

       All parameters should be	named, with identical names in the declaration
       and implementation.

       Corresponding cpplint.py	check name: readability/function.

   readability-non-const-parameter
       The  check  finds  function  parameters of a pointer type that could be
       changed to point	to a constant type instead.

       When const is used properly, many mistakes can be  avoided.  Advantages
       when using const	properly:

       o prevent unintentional modification of data;

       o get additional	warnings such as using uninitialized data;

       o make it easier	for developers to see possible side effects.

       This check is not strict	about constness, it only warns when the	const-
       ness will make the function interface safer.

	  // warning here; the declaration "const char *p" would make the function
	  // interface safer.
	  char f1(char *p) {
	    return *p;
	  }

	  // no	warning; the declaration could be more const "const int	* const	p" but
	  // that does not make	the function interface safer.
	  int f2(const int *p) {
	    return *p;
	  }

	  // no	warning; making	x const	does not make the function interface safer
	  int f3(int x)	{
	    return x;
	  }

	  // no	warning; Technically, *p can be	const ("const struct S *p"). But making
	  // *p	const could be misleading. People might	think that it's	safe to	pass
	  // const data	to this	function.
	  struct S { int *a; int *b; };
	  int f3(struct	S *p) {
	    *(p->a) = 0;
	  }

   readability-redundant-control-flow
       This check looks	for procedures (functions returning no value) with re-
       turn  statements	at the end of the function. Such return	statements are
       redundant.

       Loop statements (for, while, do while) are checked for  redundant  con-
       tinue statements	at the end of the loop body.

       Examples:

       The following function f	contains a redundant return statement:

	  extern void g();
	  void f() {
	    g();
	    return;
	  }

       becomes

	  extern void g();
	  void f() {
	    g();
	  }

       The following function k	contains a redundant continue statement:

	  void k() {
	    for	(int i = 0; i <	10; ++i) {
	      continue;
	    }
	  }

       becomes

	  void k() {
	    for	(int i = 0; i <	10; ++i) {
	    }
	  }

   readability-redundant-declaration
       Finds redundant variable	and function declarations.

	  extern int X;
	  extern int X;

       becomes

	  extern int X;

       Such redundant declarations can be removed without changing program be-
       haviour.	 They can for instance be unintentional	left overs from	previ-
       ous refactorings	when code has been moved around. Having	redundant dec-
       larations could in worst	case mean that there are  typos	 in  the  code
       that cause bugs.

       Normally	the code can be	automatically fixed, clang-tidy	can remove the
       second declaration. However there are 2 cases when you need to fix  the
       code manually:

       o When the declarations are in different	header files;

       o When multiple variables are declared together.

   Options
       IgnoreMacros
	      If  set  to  non-zero,  the  check will not give warnings	inside
	      macros. Default is 1.

   readability-redundant-function-ptr-dereference
       Finds redundant dereferences of a function pointer.

       Before:

	  int f(int,int);
	  int (*p)(int,	int) = &f;

	  int i	= (**p)(10, 50);

       After:

	  int f(int,int);
	  int (*p)(int,	int) = &f;

	  int i	= (*p)(10, 50);

   readability-redundant-member-init
       Finds member initializations that are unnecessary because the same  de-
       fault constructor would be called if they were not present.

       Example:

	  // Explicitly	initializing the member	s is unnecessary.
	  class	Foo {
	  public:
	    Foo() : s()	{}

	  private:
	    std::string	s;
	  };

   readability-redundant-preprocessor
       Finds  potentially redundant preprocessor directives. At	the moment the
       following cases are detected:

       o #ifdef	.. #endif pairs	which are nested inside	an outer pair with the
	 same condition. For example:

	  #ifdef FOO
	  #ifdef FOO //	inner ifdef is considered redundant
	  void f();
	  #endif
	  #endif

       o Same for #ifndef .. #endif pairs. For example:

	  #ifndef FOO
	  #ifndef FOO // inner ifndef is considered redundant
	  void f();
	  #endif
	  #endif

       o #ifndef inside	an #ifdef with the same	condition:

	  #ifdef FOO
	  #ifndef FOO // inner ifndef is considered redundant
	  void f();
	  #endif
	  #endif

       o #ifdef	inside an #ifndef with the same	condition:

	  #ifndef FOO
	  #ifdef FOO //	inner ifdef is considered redundant
	  void f();
	  #endif
	  #endif

       o #if  ..  #endif  pairs	which are nested inside	an outer pair with the
	 same condition. For example:

	  #define FOO 4
	  #if FOO == 4
	  #if FOO == 4 // inner	if is considered redundant
	  void f();
	  #endif
	  #endif

   readability-redundant-smartptr-get
       Find and	remove redundant calls to smart	pointer's .get() method.

       Examples:

	  ptr.get()->Foo()  ==>	 ptr->Foo()
	  *ptr.get()  ==>  *ptr
	  *ptr->get()  ==>  **ptr
	  if (ptr.get()	== nullptr) ...	=> if (ptr == nullptr) ...

       IgnoreMacros
	      If this option is	set to non-zero	(default is 1),	the check will
	      not warn about calls inside macros.

   readability-redundant-string-cstr
       Finds	 unnecessary	 calls	   to	  std::string::c_str()	   and
       std::string::data().

   readability-redundant-string-init
       Finds unnecessary string	initializations.

       Examples:

	  // Initializing string with empty string literal is unnecessary.
	  std::string a	= "";
	  std::string b("");

	  // becomes

	  std::string a;
	  std::string b;

   readability-simplify-boolean-expr
       Looks for boolean expressions involving boolean constants  and  simpli-
       fies them to use	the appropriate	boolean	expression directly.

       Examples:

		      +---------------------------+------------+
		      |Initial expression	  | Result     |
		      +---------------------------+------------+
		      |if (b ==	true)		  | if (b)     |
		      +---------------------------+------------+
		      |if (b ==	false)		  | if (!b)    |
		      +---------------------------+------------+
		      |if (b &&	true)		  | if (b)     |
		      +---------------------------+------------+
		      |if (b &&	false)		  | if (false) |
		      +---------------------------+------------+
		      |if (b ||	true)		  | if (true)  |
		      +---------------------------+------------+
		      |if (b ||	false)		  | if (b)     |
		      +---------------------------+------------+
		      |e ? true	: false		  | e	       |
		      +---------------------------+------------+
		      |e ? false : true		  | !e	       |
		      +---------------------------+------------+
		      |if (true) t(); else f();	  | t();       |
		      +---------------------------+------------+
		      |if (false) t(); else f();  | f();       |
		      +---------------------------+------------+
		      |if  (e)	return true; else | return e;  |
		      |return false;		  |	       |
		      +---------------------------+------------+
		      |if (e) return false;  else | return !e; |
		      |return true;		  |	       |
		      +---------------------------+------------+
		      |if  (e) b = true; else b	= | b =	e;     |
		      |false;			  |	       |
		      +---------------------------+------------+
		      |if (e) b	= false; else b	= | b =	!e;    |
		      |true;			  |	       |
		      +---------------------------+------------+
		      |if (e) return true; return | return e;  |
		      |false;			  |	       |
		      +---------------------------+------------+
		      |if (e) return  false;  re- | return !e; |
		      |turn true;		  |	       |
		      +---------------------------+------------+

       The resulting expression	e is modified as follows:

	      1. Unnecessary parentheses around	the expression are removed.

	      2. Negated applications of ! are eliminated.

	      3. Negated  applications	of comparison operators	are changed to
		 use the opposite condition.

	      4. Implicit conversions of pointers, including pointers to  mem-
		 bers,	to  bool  are  replaced	 with  explicit	comparisons to
		 nullptr in C++11 or NULL in C++98/03.

	      5. Implicit casts	to bool	are replaced with  explicit  casts  to
		 bool.

	      6. Object	expressions with explicit operator bool	conversion op-
		 erators are replaced with explicit casts to bool.

	      7. Implicit conversions of integral types	to bool	 are  replaced
		 with explicit comparisons to 0.

       Examples:

	      1. The  ternary  assignment bool b = (i <	0) ? true : false; has
		 redundant parentheses and becomes bool	b = i <	0;.

	      2. The conditional return	if (!b)	return false; return true; has
		 an implied double negation and	becomes	return b;.

	      3. The  conditional return if (i < 0) return false; return true;
		 becomes return	i >= 0;.

		 The conditional return	if (i != 0) return false; return true;
		 becomes return	i == 0;.

	      4. The  conditional return if (p)	return true; return false; has
		 an implicit conversion	of a pointer to	bool and  becomes  re-
		 turn p	!= nullptr;.

		 The  ternary  assignment bool b = (i &	1) ? true : false; has
		 an implicit conversion	of i & 1 to bool and becomes bool b  =
		 (i & 1) != 0;.

	      5. The  conditional  return  if (i & 1) return true; else	return
		 false;	has an implicit	conversion of an integer quantity i  &
		 1 to bool and becomes return (i & 1) != 0;

	      6. Given	struct	X  {  explicit operator	bool();	};, and	an in-
		 stance	x of struct X, the conditional return  if  (x)	return
		 true; return false; becomes return static_cast<bool>(x);

   Options
       ChainedConditionalReturn
	      If non-zero, conditional boolean return statements at the	end of
	      an if/else if chain will be transformed. Default is 0.

       ChainedConditionalAssignment
	      If non-zero, conditional boolean assignments at the  end	of  an
	      if/else if chain will be transformed. Default is 0.

   readability-simplify-subscript-expr
       This  check  simplifies	subscript  expressions.	 Currently this	covers
       calling .data() and immediately doing an	array subscript	 operation  to
       obtain  a  single element, in which case	simply calling operator[] suf-
       fice.

       Examples:

	  std::string s	= ...;
	  char c = s.data()[i];	 // char c = s[i];

   Options
       Types  The list	of  type(s)  that  triggers  this  check.  Default  is
	      ::std::basic_string;::std::basic_string_view;::std::vec-
	      tor;::std::array

   readability-static-accessed-through-instance
       Checks for member expressions that access static	 members  through  in-
       stances,	and replaces them with uses of the appropriate qualified-id.

       Example:

       The following code:

	  struct C {
	    static void	foo();
	    static int x;
	  };

	  C *c1	= new C();
	  c1->foo();
	  c1->x;

       is changed to:

	  C *c1	= new C();
	  C::foo();
	  C::x;

   readability-static-definition-in-anonymous-namespace
       Finds static function and variable definitions in anonymous namespace.

       In  this	 case, static is redundant, because anonymous namespace	limits
       the visibility of definitions to	a single translation unit.

	  namespace {
	    static int a = 1; // Warning.
	    static const b = 1;	// Warning.
	  }

       The check will apply a fix by removing the redundant static qualifier.

   readability-string-compare
       Finds string comparisons	using the compare method.

       A common	mistake	is to use the string's compare method instead of using
       the  equality  or  inequality operators.	The compare method is intended
       for sorting functions and thus returns a	negative  number,  a  positive
       number  or  zero	 depending on the lexicographical relationship between
       the strings compared.  If an equality or	inequality check can  suffice,
       that is recommended. This is recommended	to avoid the risk of incorrect
       interpretation of the return value and to simplify the code. The	string
       equality	 and  inequality operators can also be faster than the compare
       method due to early termination.

       Examples:

	  std::string str1{"a"};
	  std::string str2{"b"};

	  // use str1 != str2 instead.
	  if (str1.compare(str2)) {
	  }

	  // use str1 == str2 instead.
	  if (!str1.compare(str2)) {
	  }

	  // use str1 == str2 instead.
	  if (str1.compare(str2) == 0) {
	  }

	  // use str1 != str2 instead.
	  if (str1.compare(str2) != 0) {
	  }

	  // use str1 == str2 instead.
	  if (0	== str1.compare(str2)) {
	  }

	  // use str1 != str2 instead.
	  if (0	!= str1.compare(str2)) {
	  }

	  // Use str1 == "foo" instead.
	  if (str1.compare("foo") == 0)	{
	  }

       The above code examples shows the list of if-statements that this check
       will  give a warning for. All of	them uses compare to check if equality
       or inequality of	two strings instead of using the correct operators.

   readability-uniqueptr-delete-release
       Replace delete <unique_ptr>.release() with <unique_ptr> = nullptr.  The
       latter  is  shorter,  simpler  and  does	not require use	of raw pointer
       APIs.

	  std::unique_ptr<int> P;
	  delete P.release();

	  // becomes

	  std::unique_ptr<int> P;
	  P = nullptr;

   readability-uppercase-literal-suffix
       cert-dcl16-c redirects here as an alias for this	 check.	  By  default,
       only  the  suffixes  that  begin	with l (l, ll, lu, llu,	but not	u, ul,
       ull) are	diagnosed by that alias.

       hicpp-uppercase-literal-suffix redirects	here  as  an  alias  for  this
       check.

       Detects	when  the integral literal or floating point (decimal or hexa-
       decimal)	literal	has a non-uppercase suffix and provides	a fix-it  hint
       with the	uppercase suffix.

       All valid combinations of suffixes are supported.

	  auto x = 1;  // OK, no suffix.

	  auto x = 1u; // warning: integer literal suffix 'u' is not upper-case

	  auto x = 1U; // OK, suffix is	uppercase.

	  ...

   Options
       NewSuffixes
	      Optionally,  a list of the destination suffixes can be provided.
	      When the suffix is found,	a case-insensitive lookup in that list
	      is  made,	 and  if a replacement is found	that is	different from
	      the current suffix, then the diagnostic is issued.  This	allows
	      for  fine-grained	 control of what suffixes to consider and what
	      their replacements should	be.

   Example
       Given a list L;uL:

       o l -> L

       o L will	be kept	as is.

       o ul -> uL

       o Ul -> uL

       o UL -> uL

       o uL will be kept as is.

       o ull will be kept as is, since it is not in the	list

       o and so	on.

       IgnoreMacros
	      If this option is	set to non-zero	(default is 1),	the check will
	      not warn about literal suffixes inside macros.

   zircon-temporary-objects
       Warns  on construction of specific temporary objects in the Zircon ker-
       nel.  If	the object should be flagged, If the object should be flagged,
       the fully qualified type	name must be explicitly	passed to the check.

       For  example, given the list of classes "Foo" and "NS::Bar", all	of the
       following will trigger the warning:

	  Foo();
	  Foo F	= Foo();
	  func(Foo());

	  namespace NS {

	  Bar();

	  }

       With the	same list, the following will not trigger the warning:

	  Foo F;					 // Non-temporary construction okay
	  Foo F(param);			     //	Non-temporary construction okay
	  Foo *F = new Foo();	   // New construction okay

	  Bar();					 // Not	NS::Bar, so okay
	  NS::Bar B;			       // Non-temporary	construction okay

       Note that objects must be explicitly specified in order to be  flagged,
       and so objects that inherit a specified object will not be flagged.

       This check matches temporary objects without regard for inheritance and
       so a prohibited base class type does  not  similarly  prohibit  derived
       class types.

	  class	Derived	: Foo {} // Derived is not explicitly disallowed
	  Derived();		 // and	so temporary construction is okay

   Options
       Names  A	 semi-colon-separated  list  of	 fully-qualified  names	of C++
	      classes that should not be constructed as	 temporaries.  Default
	      is empty.

   Clang-tidy IDE/Editor Integrations
       Apart from being	a standalone tool, clang-tidy is integrated into vari-
       ous IDEs, code analyzers, and editors. Besides, it is  currently	 being
       integrated  into	 Clangd. The following table shows the most well-known
       clang-tidy integrations in detail.

  +------------+------------+-------------+-------------+-------------+------------+
  |	       | Feature    |		  |		|	      |		   |
  +------------+------------+-------------+-------------+-------------+------------+
  |Tool	       | On-the-fly | Check  list | Options  to	| Configura-  |	Custom	   |
  |	       | inspection | configura-  | checks	| tion	  via |	clang-tidy |
  |	       |	    | tion (GUI)  | (GUI)	| .clang-tidy |	binary	   |
  |	       |	    |		  |		| files	      |		   |
  +------------+------------+-------------+-------------+-------------+------------+
  |A.L.E.  for | +	    | -		  | -		| -	      |	+	   |
  |Vim	       |	    |		  |		|	      |		   |
  +------------+------------+-------------+-------------+-------------+------------+
  |Clang Power | -	    | +		  | -		| +	      |	-	   |
  |Tools   for |	    |		  |		|	      |		   |
  |Visual Stu- |	    |		  |		|	      |		   |
  |dio	       |	    |		  |		|	      |		   |
  +------------+------------+-------------+-------------+-------------+------------+

  |Clangd      | +	    | -		  | -		| -	      |	-	   |
  +------------+------------+-------------+-------------+-------------+------------+
  |CLion IDE   | +	    | +		  | +		| +	      |	+	   |
  +------------+------------+-------------+-------------+-------------+------------+
  |CodeChecker | -	    | -		  | -		| -	      |	+	   |
  +------------+------------+-------------+-------------+-------------+------------+
  |CPPCheck    | -	    | -		  | -		| -	      |	-	   |
  +------------+------------+-------------+-------------+-------------+------------+
  |CPPDepend   | -	    | -		  | -		| -	      |	-	   |
  +------------+------------+-------------+-------------+-------------+------------+
  |Flycheck    | +	    | -		  | -		| +	      |	+	   |
  |for Emacs   |	    |		  |		|	      |		   |
  +------------+------------+-------------+-------------+-------------+------------+
  |KDevelop    | -	    | +		  | +		| +	      |	+	   |
  |IDE	       |	    |		  |		|	      |		   |
  +------------+------------+-------------+-------------+-------------+------------+
  |Qt  Creator | +	    | +		  | -		| +	      |	+	   |
  |IDE	       |	    |		  |		|	      |		   |
  +------------+------------+-------------+-------------+-------------+------------+
  |ReSharper   | +	    | +		  | -		| +	      |	+	   |
  |C++	   for |	    |		  |		|	      |		   |
  |Visual Stu- |	    |		  |		|	      |		   |
  |dio	       |	    |		  |		|	      |		   |
  +------------+------------+-------------+-------------+-------------+------------+
  |Syntastic   | +	    | -		  | -		| -	      |	+	   |
  |for Vim     |	    |		  |		|	      |		   |
  +------------+------------+-------------+-------------+-------------+------------+
  |Visual  As- | +	    | +		  | -		| -	      |	-	   |
  |sist	   for |	    |		  |		|	      |		   |
  |Visual Stu- |	    |		  |		|	      |		   |
  |dio	       |	    |		  |		|	      |		   |
  +------------+------------+-------------+-------------+-------------+------------+

       IDEs

       CLion 2017.2 and	later integrates clang-tidy as	an  extension  to  the
       built-in	 code  analyzer.  Starting from	2018.2 EAP, CLion allows using
       clang-tidy via Clangd. Inspections and applicable quick-fixes are  per-
       formed  on  the	fly,  and checks can be	configured in standard command
       line format. In this integration, you can switch	to the clang-tidy  bi-
       nary  different	from  the  bundled  one,  pass	the  configuration  in
       .clang-tidy files instead of using the IDE settings, and	configure  op-
       tions for particular checks.

       KDevelop	 with  the  kdev-clang-tidy plugin, starting from version 5.1,
       performs	static analysis	using  clang-tidy.  The	 plugin	 launches  the
       clang-tidy  binary from the specified location and parses its output to
       provide a list of issues.

       QtCreator 4.6 integrates	clang-tidy warnings into the  editor  diagnos-
       tics  under  the	 Clang	Code Model. To employ clang-tidy inspection in
       QtCreator, you need to create a copy of one of the presets  and	choose
       the  checks  to be performed. Since QtCreator 4.7 project-wide analysis
       is possible with	the Clang Tools	analyzer.

       MS Visual Studio	has a native clang-tidy-vs plugin and also  can	 inte-
       grate  clang-tidy  by means of three other tools. The ReSharper C++ ex-
       tension,	version	2017.3 and later, provides seamless  clang-tidy	 inte-
       gration:	checks and quick-fixes run alongside native inspections. Apart
       from that, ReSharper C++	incorporates clang-tidy	as a separate step  of
       its  code  clean-up process. Visual Assist build	2210 includes a	subset
       of clang-tidy checklist to inspect the code as you edit.	  Another  way
       to  bring  clang-tidy functionality to Visual Studio is the Clang Power
       Tools plugin, which includes most of the	 clang-tidy  checks  and  runs
       them during compilation or as a separate	step of	code analysis.

       Editors

       Emacs24,	 when  expanded	 with  the  Flycheck  plugin, incorporates the
       clang-tidy inspection into the syntax analyzer. For Vim,	 you  can  use
       Syntastic, which	includes clang-tidy, or	A.L.E.,	a lint engine that ap-
       plies clang-tidy	along with other linters.

       Analyzers

       clang-tidy is integrated	in CPPDepend starting from version 2018.1  and
       CPPCheck	1.82. CPPCheck integration lets	you import Visual Studio solu-
       tions and run the clang-tidy inspection on them.	The CodeChecker	appli-
       cation  of  version  5.3	 or  later,  which  also comes as a plugin for
       Eclipse,	supports clang-tidy as a static	analysis instrument and	allows
       to use a	custom clang-tidy binary.

   Getting Involved
       clang-tidy  has	several	 own  checks and can run Clang static analyzer
       checks, but its power is	in the ability to easily write custom checks.

       Checks are organized in modules,	which can be  linked  into  clang-tidy
       with minimal or no code changes in clang-tidy.

       Checks  can  plug  into	the  analysis  on the preprocessor level using
       PPCallbacks or on the AST level using AST Matchers. When	 an  error  is
       found, checks can report	them in	a way similar to how Clang diagnostics
       work. A fix-it hint can be attached to a	diagnostic message.

       The interface provided by clang-tidy makes it easy to write useful  and
       precise	checks	in just	a few lines of code. If	you have an idea for a
       good check, the rest of this document explains how to do	this.

       There are a few tools particularly useful  when	developing  clang-tidy
       checks:

	      o	add_new_check.py is a script to	automate the process of	adding
		a new check, it	will create the	check, update the  CMake  file
		and create a test;

	      o	rename_check.py	does what the script name suggests, renames an
		existing check;

	      o	clang-query is invaluable for interactive prototyping  of  AST
		matchers and exploration of the	Clang AST;

	      o	clang-check  with the -ast-dump	(and optionally	-ast-dump-fil-
		ter) provides a	convenient way to dump AST of a	C++ program.

       If CMake	is configured  with  CLANG_ENABLE_STATIC_ANALYZER,  clang-tidy
       will  not  be built with	support	for the	clang-analyzer-* checks	or the
       mpi-* checks.

   Choosing the	Right Place for	your Check
       If you have an idea of a	check, you should decide whether it should  be
       implemented as a:

       o Clang	diagnostic:  if	the check is generic enough, targets code pat-
	 terns that most probably are bugs (rather than	style  or  readability
	 issues),  can be implemented effectively and with extremely low false
	 positive rate,	it may make a good Clang diagnostic.

       o Clang static analyzer check: if the check requires some sort of  con-
	 trol flow analysis, it	should probably	be implemented as a static an-
	 alyzer	check.

       o clang-tidy check is a good choice  for	 linter-style  checks,	checks
	 that  are related to a	certain	coding style, checks that address code
	 readability, etc.

   Preparing your Workspace
       If you are new to LLVM development, you should read the Getting Started
       with  the LLVM System, Using Clang Tools	and How	To Setup Clang Tooling
       For LLVM	documents to check out and build LLVM, Clang and  Clang	 Extra
       Tools with CMake.

       Once  you  are  done, change to the llvm/tools/clang/tools/extra	direc-
       tory, and let's start!

   The Directory Structure
       clang-tidy source code resides in the llvm/tools/clang/tools/extra  di-
       rectory and is structured as follows:

	  clang-tidy/			    # Clang-tidy core.
	  |-- ClangTidy.h		    # Interfaces for users.
	  |-- ClangTidyCheck.h		    # Interfaces for checks.
	  |-- ClangTidyModule.h		    # Interface	for clang-tidy modules.
	  |-- ClangTidyModuleRegistry.h	    # Interface	for registering	of modules.
	     ...
	  |-- google/			    # Google clang-tidy	module.
	  |-+
	    |--	GoogleTidyModule.cpp
	    |--	GoogleTidyModule.h
		  ...
	  |-- llvm/			    # LLVM clang-tidy module.
	  |-+
	    |--	LLVMTidyModule.cpp
	    |--	LLVMTidyModule.h
		  ...
	  |-- objc/			    # Objective-C clang-tidy module.
	  |-+
	    |--	ObjCTidyModule.cpp
	    |--	ObjCTidyModule.h
		  ...
	  |-- tool/			    # Sources of the clang-tidy	binary.
		  ...
	  test/clang-tidy/		    # Integration tests.
	      ...
	  unittests/clang-tidy/		    # Unit tests.
	  |-- ClangTidyTest.h
	  |-- GoogleModuleTest.cpp
	  |-- LLVMModuleTest.cpp
	  |-- ObjCModuleTest.cpp
	      ...

   Writing a clang-tidy	Check
       So you have an idea of a	useful check for clang-tidy.

       First,  if  you're not familiar with LLVM development, read through the
       Getting Started with LLVM document for instructions on setting up  your
       workflow	and the	LLVM Coding Standards document to familiarize yourself
       with the	coding style used in the project. For code reviews  we	mostly
       use LLVM	Phabricator.

       Next, you need to decide	which module the check belongs to. Modules are
       located in subdirectories of clang-tidy/	and contain checks targeting a
       certain	aspect	of code	quality	(performance, readability, etc.), cer-
       tain coding style or standard (Google, LLVM, CERT, etc.)	 or  a	widely
       used  API  (e.g.	MPI). Their names are same as user-facing check	groups
       names described above.

       After choosing  the  module  and	 the  name  for	 the  check,  run  the
       clang-tidy/add_new_check.py  script to create the skeleton of the check
       and plug	it to clang-tidy. It's	the  recommended  way  of  adding  new
       checks.

       If  we  want  to	 create	a readability-awesome-function-names, we would
       run:

	  $ clang-tidy/add_new_check.py	readability awesome-function-names

       The add_new_check.py script will:

	      o	create the class for your check	inside the specified  module's
		directory  and register	it in the module and in	the build sys-
		tem;

	      o	create a lit test file in the test/clang-tidy/ directory;

	      o	create	a  documentation  file	and  include   it   into   the
		docs/clang-tidy/checks/list.rst.

       Let's see in more detail	at the check class definition:

	  ...

	  #include "../ClangTidyCheck.h"

	  namespace clang {
	  namespace tidy {
	  namespace readability	{

	  ...
	  class	AwesomeFunctionNamesCheck : public ClangTidyCheck {
	  public:
	    AwesomeFunctionNamesCheck(StringRef	Name, ClangTidyContext *Context)
		: ClangTidyCheck(Name, Context)	{}
	    void registerMatchers(ast_matchers::MatchFinder *Finder) override;
	    void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
	  };

	  } // namespace readability
	  } // namespace tidy
	  } // namespace clang

	  ...

       Constructor  of the check receives the Name and Context parameters, and
       must forward them to the	ClangTidyCheck constructor.

       In our case the check needs to operate on the AST level	and  it	 over-
       rides  the  registerMatchers and	check methods. If we wanted to analyze
       code on the preprocessor	level, we'd need instead to override the  reg-
       isterPPCallbacks	method.

       In the registerMatchers method we create	an AST Matcher (see AST	Match-
       ers for more information) that will find	the pattern in the AST that we
       want  to	 inspect.  The results of the matching are passed to the check
       method, which can further inspect them and report diagnostics.

	  using	namespace ast_matchers;

	  void AwesomeFunctionNamesCheck::registerMatchers(MatchFinder *Finder)	{
	    Finder->addMatcher(functionDecl().bind("x"), this);
	  }

	  void AwesomeFunctionNamesCheck::check(const MatchFinder::MatchResult &Result)	{
	    const auto *MatchedDecl = Result.Nodes.getNodeAs<FunctionDecl>("x");
	    if (MatchedDecl->getName().startswith("awesome_"))
	      return;
	    diag(MatchedDecl->getLocation(), "function %0 is insufficiently awesome")
		<< MatchedDecl
		<< FixItHint::CreateInsertion(MatchedDecl->getLocation(), "awesome_");
	  }

       (If  you	 want  to  see	an  example  of	 a  useful  check,   look   at
       clang-tidy/google/ExplicitConstructorCheck.h			   and
       clang-tidy/google/ExplicitConstructorCheck.cpp).

   Registering your Check
       (The add_new_check.py takes care	of registering the check in an	exist-
       ing  module.  If	 you  want to create a new module or know the details,
       read on.)

       The check should	be registered in the corresponding module with a  dis-
       tinct name:

	  class	MyModule : public ClangTidyModule {
	   public:
	    void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override {
	      CheckFactories.registerCheck<ExplicitConstructorCheck>(
		  "my-explicit-constructor");
	    }
	  };

       Now we need to register the module in the ClangTidyModuleRegistry using
       a statically initialized	variable:

	  static ClangTidyModuleRegistry::Add<MyModule>	X("my-module",
							  "Adds	my lint	checks.");

       When using LLVM build system, we	need to	use the	following hack to  en-
       sure the	module is linked into the clang-tidy binary:

       Add this	near the ClangTidyModuleRegistry::Add<MyModule>	variable:

	  // This anchor is used to force the linker to	link in	the generated object file
	  // and thus register the MyModule.
	  volatile int MyModuleAnchorSource = 0;

       And  this to the	main translation unit of the clang-tidy	binary (or the
       binary you link the clang-tidy library  in)  clang-tidy/tool/ClangTidy-
       Main.cpp:

	  // This anchor is used to force the linker to	link the MyModule.
	  extern volatile int MyModuleAnchorSource;
	  static int MyModuleAnchorDestination = MyModuleAnchorSource;

   Configuring Checks
       If  a  check  needs configuration options, it can access	check-specific
       options using the Options.get<Type>("SomeOption", DefaultValue) call in
       the  check constructor. In this case the	check should also override the
       ClangTidyCheck::storeOptions method to make the options provided	by the
       check  discoverable. This method	lets clang-tidy	know which options the
       check implements	 and  what  the	 current  values  are  (e.g.  for  the
       -dump-config command line option).

	  class	MyCheck	: public ClangTidyCheck	{
	    const unsigned SomeOption1;
	    const std::string SomeOption2;

	  public:
	    MyCheck(StringRef Name, ClangTidyContext *Context)
	      :	ClangTidyCheck(Name, Context),
		SomeOption(Options.get("SomeOption1", -1U)),
		SomeOption(Options.get("SomeOption2", "some default")) {}

	    void storeOptions(ClangTidyOptions::OptionMap &Opts) override {
	      Options.store(Opts, "SomeOption1", SomeOption1);
	      Options.store(Opts, "SomeOption2", SomeOption2);
	    }
	    ...

       Assuming	 the  check is registered with the name	"my-check", the	option
       can then	be set in a .clang-tidy	file in	the following way:

	  CheckOptions:
	    - key: my-check.SomeOption1
	      value: 123
	    - key: my-check.SomeOption2
	      value: 'some other value'

       If you need to specify check options on a command line, you can use the
       inline YAML format:

	  $ clang-tidy -config="{CheckOptions: [{key: a, value:	b}, {key: x, value: y}]}" ...

   Testing Checks
       To run tests for	clang-tidy use the command:

	  $ ninja check-clang-tools

       clang-tidy  checks  can be tested using either unit tests or lit	tests.
       Unit tests may be more convenient to  test  complex  replacements  with
       strict  checks. Lit tests allow using partial text matching and regular
       expressions which makes them more suitable for  writing	compact	 tests
       for diagnostic messages.

       The  check_clang_tidy.py	script provides	an easy	way to test both diag-
       nostic messages and fix-its. It filters out CHECK lines from  the  test
       file, runs clang-tidy and verifies messages and fixes with two separate
       FileCheck invocations: once with	FileCheck's directive  prefix  set  to
       CHECK-MESSAGES,	validating  the	diagnostic messages, and once with the
       directive prefix	set to CHECK-FIXES, running  against  the  fixed  code
       (i.e.,  the  code  after	generated fix-its are applied).	In particular,
       CHECK-FIXES: can	be used	 to  check  that  code	was  not  modified  by
       fix-its,	 by  checking  that it is present unchanged in the fixed code.
       The full	set of FileCheck directives  is	 available  (e.g.,  CHECK-MES-
       SAGES-SAME:,  CHECK-MESSAGES-NOT:),  though  typically  the basic CHECK
       forms (CHECK-MESSAGES and CHECK-FIXES) are  sufficient  for  clang-tidy
       tests. Note that	the FileCheck documentation mostly assumes the default
       prefix  (CHECK),	 and  hence  describes	the   directive	  as   CHECK:,
       CHECK-SAME:,  CHECK-NOT:,  etc.	Replace	CHECK by either	CHECK-FIXES or
       CHECK-MESSAGES for clang-tidy tests.

       An additional check enabled  by	check_clang_tidy.py  ensures  that  if
       CHECK-MESSAGES: is used in a file then every warning or error must have
       an associated CHECK in that file. Or, you can use CHECK-NOTES: instead,
       if you want to also ensure that all the notes are checked.

       To  use the check_clang_tidy.py script, put a .cpp file with the	appro-
       priate RUN line in the test/clang-tidy directory.  Use  CHECK-MESSAGES:
       and  CHECK-FIXES: lines to write	checks against diagnostic messages and
       fixed code.

       It's advised to make the	checks as specific as possible to avoid	checks
       matching	 to  incorrect parts of	the input. Use [[@LINE+X]]/[[@LINE-X]]
       substitutions and distinct function and	variable  names	 in  the  test
       code.

       Here's  an  example of a	test using the check_clang_tidy.py script (the
       full source code	is at test/clang-tidy/google-readability-casting.cpp):

	  // RUN: %check_clang_tidy %s google-readability-casting %t

	  void f(int a)	{
	    int	b = (int)a;
	    // CHECK-MESSAGES: :[[@LINE-1]]:11:	warning: redundant cast	to the same type [google-readability-casting]
	    // CHECK-FIXES: int	b = a;
	  }

       To check	more than one scenario in the same test	file  use  -check-suf-
       fix=SUFFIX-NAME	on  check_clang_tidy.py	 command  line	or -check-suf-
       fixes=SUFFIX-NAME-1,SUFFIX-NAME-2,....	 With	-check-suffix[es]=SUF-
       FIX-NAME	 you  need  to replace your CHECK-* directives with CHECK-MES-
       SAGES-SUFFIX-NAME and CHECK-FIXES-SUFFIX-NAME.

       Here's an example:

	  // RUN: %check_clang_tidy -check-suffix=USING-A %s misc-unused-using-decls %t	-- -- -DUSING_A
	  // RUN: %check_clang_tidy -check-suffix=USING-B %s misc-unused-using-decls %t	-- -- -DUSING_B
	  // RUN: %check_clang_tidy %s misc-unused-using-decls %t
	  ...
	  // CHECK-MESSAGES-USING-A: :[[@LINE-8]]:10: warning: using decl 'A' {{.*}}
	  // CHECK-MESSAGES-USING-B: :[[@LINE-7]]:10: warning: using decl 'B' {{.*}}
	  // CHECK-MESSAGES: :[[@LINE-6]]:10: warning: using decl 'C' {{.*}}
	  // CHECK-FIXES-USING-A-NOT: using a::A;$
	  // CHECK-FIXES-USING-B-NOT: using a::B;$
	  // CHECK-FIXES-NOT: using a::C;$

       There are many dark corners in the C++ language,	and it may  be	diffi-
       cult  to	 make your check work perfectly	in all cases, especially if it
       issues fix-it hints. The	most frequent pitfalls	are  macros  and  tem-
       plates:

       1. code	written	in a macro body/template definition may	have a differ-
	  ent meaning depending	on the macro expansion/template	instantiation;

       2. multiple macro expansions/template instantiations may	result in  the
	  same	code  being  inspected	by the check multiple times (possibly,
	  with different meanings, see 1), and the same	warning	(or a slightly
	  different one) may be	issued by the check multiple times; clang-tidy
	  will deduplicate _identical_	warnings,  but	if  the	 warnings  are
	  slightly  different, all of them will	be shown to the	user (and used
	  for applying fixes, if any);

       3. making replacements to a macro body/template definition may be  fine
	  for  some macro expansions/template instantiations, but easily break
	  some other expansions/instantiations.

   Running clang-tidy on LLVM
       To test a check it's best to try	it out on a larger code	base. LLVM and
       Clang  are  the	natural	 targets  as  you already have the source code
       around. The most	convenient way to run clang-tidy  is  with  a  compile
       command	database; CMake	can automatically generate one,	for a descrip-
       tion of how to enable it	see How	To Setup Clang Tooling For LLVM.  Once
       compile_commands.json  is  in place and a working version of clang-tidy
       is  in	PATH   the   entire   code   base   can	  be   analyzed	  with
       clang-tidy/tool/run-clang-tidy.py.  The script executes clang-tidy with
       the default set of checks on every translation unit in the compile com-
       mand  database  and  displays  the  resulting  warnings and errors. The
       script provides multiple	configuration flags.

       o The default set of checks can be overridden using the	-checks	 argu-
	 ment,	taking	the  identical	format as clang-tidy does. For example
	 -checks=-*,modernize-use-override will	run the	modernize-use-override
	 check only.

       o To  restrict the files	examined you can provide one or	more regex ar-
	 guments that the file names are matched  against.   run-clang-tidy.py
	 clang-tidy/.*Check\.cpp  will	only analyze clang-tidy	checks.	It may
	 also be necessary to restrict the header files	warnings are displayed
	 from  using  the -header-filter flag. It has the same behavior	as the
	 corresponding clang-tidy flag.

       o To apply suggested fixes -fix can be  passed  as  an  argument.  This
	 gathers  all changes in a temporary directory and applies them. Pass-
	 ing -format will run clang-format over	changed	lines.

   On checks profiling
       clang-tidy can collect per-check	profiling info,	and output it for each
       processed source	file (translation unit).

       To  enable profiling info collection, use the -enable-check-profile ar-
       gument.	The timings will be output to stderr as	a table. Example  out-
       put:

	  $ clang-tidy -enable-check-profile -checks=-*,readability-function-size source.cpp
	  ===-------------------------------------------------------------------------===
				    clang-tidy checks profiling
	  ===-------------------------------------------------------------------------===
	    Total Execution Time: 1.0282 seconds (1.0258 wall clock)

	     ---User Time---   --System	Time--	 --User+System--   ---Wall Time---  ---	Name ---
	     0.9136 (100.0%)   0.1146 (100.0%)	 1.0282	(100.0%)   1.0258 (100.0%)  readability-function-size
	     0.9136 (100.0%)   0.1146 (100.0%)	 1.0282	(100.0%)   1.0258 (100.0%)  Total

       It can also store that data as JSON files for further processing. Exam-
       ple output:

	  $ clang-tidy -enable-check-profile -store-check-profile=.  -checks=-*,readability-function-size source.cpp
	  $ # Note that	there won't be timings table printed to	the console.
	  $ ls /tmp/out/
	  20180516161318717446360-source.cpp.json
	  $ cat	20180516161318717446360-source.cpp.json
	  {
	  "file": "/path/to/source.cpp",
	  "timestamp": "2018-05-16 16:13:18.717446360",
	  "profile": {
	    "time.clang-tidy.readability-function-size.wall": 1.0421266555786133e+00,
	    "time.clang-tidy.readability-function-size.user": 9.2088400000005421e-01,
	    "time.clang-tidy.readability-function-size.sys": 1.2418899999999974e-01
	  }
	  }

       There is	only one argument that controls	profile	storage:

       o -store-check-profile=<prefix>

	 By default reports are	printed	in tabulated format  to	 stderr.  When
	 this  option  is  passed, these per-TU	profiles are instead stored as
	 JSON.	If the prefix is not an	absolute path, it is considered	to  be
	 relative  to  the directory from where	you have run clang-tidy. All .
	 and ..	 patterns in the path are  collapsed,  and  symlinks  are  re-
	 solved.

	 Example:  Let's suppose you have a source file	named example.cpp, lo-
	 cated in the /source directory. Only the input	filename is used,  not
	 the  full  path to the	source file. Additionally, it is prefixed with
	 the current timestamp.

	 o If you specify -store-check-profile=/tmp, then the profile will  be
	   saved to /tmp/<ISO8601-like timestamp>-example.cpp.json

	 o If  you  run	 clang-tidy  from  within  /foo	directory, and specify
	   -store-check-profile=., then	the profile will  still	 be  saved  to
	   /foo/<ISO8601-like timestamp>-example.cpp.json

       clang-tidy  is  a clang-based C++ "linter" tool.	Its purpose is to pro-
       vide an extensible framework for	diagnosing and fixing typical program-
       ming  errors, like style	violations, interface misuse, or bugs that can
       be deduced via static analysis. clang-tidy is modular  and  provides  a
       convenient interface for	writing	new checks.

   Using clang-tidy
       clang-tidy  is a	LibTooling-based tool, and it's	easier to work with if
       you set up a compile command database for your project (for an  example
       of  how	to  do	this  see How To Setup Tooling For LLVM). You can also
       specify compilation options on the command line after --:

	  $ clang-tidy test.cpp	-- -Imy_project/include	-DMY_DEFINES ...

       clang-tidy has its own checks and can also run  Clang  static  analyzer
       checks. Each check has a	name and the checks to run can be chosen using
       the -checks= option, which specifies a comma-separated list of positive
       and  negative  (prefixed	 with  -) globs. Positive globs	add subsets of
       checks, negative	globs remove them. For example,

	  $ clang-tidy test.cpp	-checks=-*,clang-analyzer-*,-clang-analyzer-cplusplus*

       will disable all	default	checks (-*) and	 enable	 all  clang-analyzer-*
       checks except for clang-analyzer-cplusplus* ones.

       The -list-checks	option lists all the enabled checks. When used without
       -checks=, it shows checks enabled by default. Use -checks=* to see  all
       available  checks  or  with  any	 other	value of -checks= to see which
       checks are enabled by this value.

       There are currently the following groups	of checks:

		  +-------------------+----------------------------+
		  |Name	prefix	      |	Description		   |
		  +-------------------+----------------------------+
		  |abseil-	      |	Checks related	to  Abseil |
		  |		      |	library.		   |
		  +-------------------+----------------------------+
		  |android-	      |	Checks related to Android. |
		  +-------------------+----------------------------+
		  |boost-	      |	Checks	related	 to  Boost |
		  |		      |	library.		   |
		  +-------------------+----------------------------+
		  |bugprone-	      |	Checks	that  target  bug- |
		  |		      |	prone code constructs.	   |
		  +-------------------+----------------------------+
		  |cert-	      |	Checks related to CERT Se- |
		  |		      |	cure Coding Guidelines.	   |
		  +-------------------+----------------------------+
		  |cppcoreguidelines- |	Checks related to C++ Core |
		  |		      |	Guidelines.		   |
		  +-------------------+----------------------------+
		  |clang-analyzer-    |	Clang	 Static	  Analyzer |
		  |		      |	checks.			   |
		  +-------------------+----------------------------+
		  |fuchsia-	      |	Checks related to  Fuchsia |
		  |		      |	coding conventions.	   |
		  +-------------------+----------------------------+
		  |google-	      |	Checks	related	 to Google |
		  |		      |	coding conventions.	   |
		  +-------------------+----------------------------+
		  |hicpp-	      |	Checks related to High In- |
		  |		      |	tegrity	 C++  Coding Stan- |
		  |		      |	dard.			   |
		  +-------------------+----------------------------+
		  |llvm-	      |	Checks related to the LLVM |
		  |		      |	coding conventions.	   |
		  +-------------------+----------------------------+
		  |misc-	      |	Checks that we didn't have |
		  |		      |	a better category for.	   |
		  +-------------------+----------------------------+
		  |modernize-	      |	Checks that advocate usage |
		  |		      |	of modern (currently "mod- |
		  |		      |	ern" means  "C++11")  lan- |
		  |		      |	guage constructs.	   |
		  +-------------------+----------------------------+
		  |mpi-		      |	Checks	 related   to  MPI |
		  |		      |	(Message  Passing   Inter- |
		  |		      |	face).			   |
		  +-------------------+----------------------------+
		  |objc-	      |	Checks	related	 to Objec- |
		  |		      |	tive-C coding conventions. |
		  +-------------------+----------------------------+
		  |openmp-	      |	Checks related	to  OpenMP |
		  |		      |	API.			   |
		  +-------------------+----------------------------+
		  |performance-	      |	Checks that target perfor- |
		  |		      |	mance-related issues.	   |
		  +-------------------+----------------------------+
		  |portability-	      |	Checks that target  porta- |
		  |		      |	bility-related issues that |
		  |		      |	don't relate to	 any  par- |
		  |		      |	ticular	coding style.	   |
		  +-------------------+----------------------------+
		  |readability-	      |	Checks	that  target read- |
		  |		      |	ability-related	    issues |
		  |		      |	that  don't  relate to any |
		  |		      |	particular coding style.   |
		  +-------------------+----------------------------+

		  |zircon-	      |	Checks related	to  Zircon |
		  |		      |	kernel coding conventions. |
		  +-------------------+----------------------------+

       Clang  diagnostics  are	treated	in a similar way as check diagnostics.
       Clang diagnostics are displayed by clang-tidy and can be	 filtered  out
       using  -checks=	option.	 However,  the -checks=	option does not	affect
       compilation arguments, so it can	not turn on Clang warnings  which  are
       not  already turned on in build configuration. The -warnings-as-errors=
       option upgrades any warnings emitted under the -checks= flag to	errors
       (but it does not	enable any checks itself).

       Clang  diagnostics  have	 check	names starting with clang-diagnostic-.
       Diagnostics which  have	a  corresponding  warning  option,  are	 named
       clang-diagnostic-<warning-option>,  e.g.	 Clang	warning	 controlled by
       -Wliteral-conversion will be reported with  check  name	clang-diagnos-
       tic-literal-conversion.

       The  -fix flag instructs	clang-tidy to fix found	errors if supported by
       corresponding checks.

       An overview of all the command-line options:

	  $ clang-tidy --help
	  USAGE: clang-tidy [options] <source0>	[... <sourceN>]

	  OPTIONS:

	  Generic Options:

	    --help			   - Display available options (--help-hidden for more)
	    --help-list			   - Display list of available options (--help-list-hidden for more)
	    --version			   - Display the version of this program

	  clang-tidy options:

	    --checks=<string>		   -
					     Comma-separated list of globs with	optional '-'
					     prefix. Globs are processed in order of
					     appearance	in the list. Globs without '-'
					     prefix add	checks with matching names to the
					     set, globs	with the '-' prefix remove checks
					     with matching names from the set of enabled
					     checks. This option's value is appended to	the
					     value of the 'Checks' option in .clang-tidy
					     file, if any.
	    --config=<string>		   -
					     Specifies a configuration in YAML/JSON format:
					       -config="{Checks: '*',
							 CheckOptions: [{key: x,
									 value:	y}]}"
					     When the value is empty, clang-tidy will
					     attempt to	find a file named .clang-tidy for
					     each source file in its parent directories.
	    --dump-config		   -
					     Dumps configuration in the	YAML format to
					     stdout. This option can be	used along with	a
					     file name (and '--' if the	file is	outside	of a
					     project with configured compilation database).
					     The configuration used for	this file will be
					     printed.
					     Use along with -checks=* to include
					     configuration of all checks.
	    --enable-check-profile	   -
					     Enable per-check timing profiles, and print a
					     report to stderr.
	    --explain-config		   -
					     For each enabled check explains, where it is
					     enabled, i.e. in clang-tidy binary, command
					     line or a specific	configuration file.
	    --export-fixes=<filename>	   -
					     YAML file to store	suggested fixes	in. The
					     stored fixes can be applied to the	input source
					     code with clang-apply-replacements.
	    --extra-arg=<string>	   - Additional	argument to append to the compiler command line
	    --extra-arg-before=<string>	   - Additional	argument to prepend to the compiler command line
	    --fix			   -
					     Apply suggested fixes. Without -fix-errors
					     clang-tidy	will bail out if any compilation
					     errors were found.
	    --fix-errors		   -
					     Apply suggested fixes even	if compilation
					     errors were found.	If compiler errors have
					     attached fix-its, clang-tidy will apply them as
					     well.
	    --format-style=<string>	   -
					     Style for formatting code around applied fixes:
					       - 'none'	(default) turns	off formatting
					       - 'file'	(literally 'file', not a placeholder)
						 uses .clang-format file in the	closest	parent
						 directory
					       - '{ <json> }' specifies	options	inline,	e.g.
						 -format-style='{BasedOnStyle: llvm, IndentWidth: 8}'
					       - 'llvm', 'google', 'webkit', 'mozilla'
					     See clang-format documentation for	the up-to-date
					     information about formatting styles and options.
					     This option overrides the 'FormatStyle` option in
					     .clang-tidy file, if any.
	    --header-filter=<string>	   -
					     Regular expression	matching the names of the
					     headers to	output diagnostics from. Diagnostics
					     from the main file	of each	translation unit are
					     always displayed.
					     Can be used together with -line-filter.
					     This option overrides the 'HeaderFilterRegex'
					     option in .clang-tidy file, if any.
	    --line-filter=<string>	   -
					     List of files with	line ranges to filter the
					     warnings. Can be used together with
					     -header-filter. The format	of the list is a
					     JSON array	of objects:
					       [
						 {"name":"file1.cpp","lines":[[1,3],[5,7]]},
						 {"name":"file2.h"}
					       ]
	    --list-checks		   -
					     List all enabled checks and exit. Use with
					     -checks=* to list all available checks.
	    -p=<string>			   - Build path
	    --quiet			   -
					     Run clang-tidy in quiet mode. This	suppresses
					     printing statistics about ignored warnings	and
					     warnings treated as errors	if the respective
					     options are specified.
	    --store-check-profile=<prefix> -
					     By	default	reports	are printed in tabulated
					     format to stderr. When this option	is passed,
					     these per-TU profiles are instead stored as JSON.
	    --system-headers		   - Display the errors	from system headers.
	    --vfsoverlay=<filename>	   -
					     Overlay the virtual filesystem described by file
					     over the real file	system.
	    --warnings-as-errors=<string>  -
					     Upgrades warnings to errors. Same format as
					     '-checks'.
					     This option's value is appended to	the value of
					     the 'WarningsAsErrors' option in .clang-tidy
					     file, if any.

	  -p <build-path> is used to read a compile command database.

		  For example, it can be a CMake build directory in which a file named
		  compile_commands.json	exists (use -DCMAKE_EXPORT_COMPILE_COMMANDS=ON
		  CMake	option to get this output). When no build path is specified,
		  a search for compile_commands.json will be attempted through all
		  parent paths of the first input file . See:
		  https://clang.llvm.org/docs/HowToSetupToolingForLLVM.html for	an
		  example of setting up	Clang Tooling on a source tree.

	  <source0> ...	specify	the paths of source files. These paths are
		  looked up in the compile command database. If	the path of a file is
		  absolute, it needs to	point into CMake's source tree.	If the path is
		  relative, the	current	working	directory needs	to be in the CMake
		  source tree and the file must	be in a	subdirectory of	the current
		  working directory. "./" prefixes in the relative files will be
		  automatically	removed, but the rest of a relative path must be a
		  suffix of a path in the compile command database.

	  Configuration	files:
	    clang-tidy attempts	to read	configuration for each source file from	a
	    .clang-tidy	file located in	the closest parent directory of	the source
	    file. If any configuration options have a corresponding command-line
	    option, command-line option	takes precedence. The effective
	    configuration can be inspected using -dump-config:

	      $	clang-tidy -dump-config
	      ---
	      Checks:	       '-*,some-check'
	      WarningsAsErrors:	''
	      HeaderFilterRegex: ''
	      FormatStyle:     none
	      User:	       user
	      CheckOptions:
		- key:		   some-check.SomeOption
		  value:	   'some value'
	      ...

   Suppressing Undesired Diagnostics
       clang-tidy diagnostics are intended to call out code that does not  ad-
       here  to	 a  coding  standard, or is otherwise problematic in some way.
       However,	if the code is known to	be correct, it may be  useful  to  si-
       lence the warning.  Some	clang-tidy checks provide a check-specific way
       to silence the diagnostics, e.g.	 bugprone-use-after-move  can  be  si-
       lenced  by  re-initializing  the	 variable after	it has been moved out,
       bugprone-string-integer-assignment  can	be  suppressed	by  explicitly
       casting	the  integer to	char, readability-implicit-bool-conversion can
       also be suppressed by using explicit casts, etc.

       If a specific suppression mechanism is  not  available  for  a  certain
       warning,	 or  its  use is not desired for some reason, clang-tidy has a
       generic mechanism to  suppress  diagnostics  using  NOLINT  or  NOLINT-
       NEXTLINE	comments.

       The  NOLINT comment instructs clang-tidy	to ignore warnings on the same
       line (it	doesn't	apply to a function, a block of	code or	any other lan-
       guage construct,	it applies to the line of code it is on). If introduc-
       ing the comment in the same line	would change the formatting  in	 unde-
       sired  way,  the	 NOLINTNEXTLINE	 comment allows	to suppress clang-tidy
       warnings	on the next line.

       Both comments can be followed by	an optional list  of  check  names  in
       parentheses (see	below for the formal syntax).

       For example:

	  class	Foo {
	    // Suppress	all the	diagnostics for	the line
	    Foo(int param); // NOLINT

	    // Consider	explaining the motivation to suppress the warning.
	    Foo(char param); //	NOLINT:	Allow implicit conversion from `char`, because <some valid reason>.

	    // Silence only the	specified checks for the line
	    Foo(double param); // NOLINT(google-explicit-constructor, google-runtime-int)

	    // Silence only the	specified diagnostics for the next line
	    // NOLINTNEXTLINE(google-explicit-constructor, google-runtime-int)
	    Foo(bool param);
	  };

       The formal syntax of NOLINT/NOLINTNEXTLINE is the following:

	  lint-comment:
	    lint-command
	    lint-command lint-args

	  lint-args:
	    ( check-name-list )

	  check-name-list:
	    check-name
	    check-name-list , check-name

	  lint-command:
	    NOLINT
	    NOLINTNEXTLINE

       Note  that  whitespaces	between	 NOLINT/NOLINTNEXTLINE and the opening
       parenthesis are not allowed (in this case the comment will  be  treated
       just as NOLINT/NOLINTNEXTLINE), whereas in check	names list (inside the
       parenthesis) whitespaces	can be used and	will be	ignored.

CLANG-INCLUDE-FIXER
   Contents
       o Clang-Include-Fixer

	 o Setup

	   o Creating a	Symbol Index From a Compilation	Database

	   o Integrate with Vim

	   o Integrate with Emacs

	 o How it Works

       One of the major	nuisances of C++ compared to other  languages  is  the
       manual  management  of  #include	 directives  in	 any  file.  clang-in-
       clude-fixer addresses one aspect	of this	problem	by providing an	 auto-
       mated  way  of  adding  #include	 directives for	missing	symbols	in one
       translation unit.

       While inserting	missing	 #include,  clang-include-fixer	 adds  missing
       namespace  qualifiers to	all instances of an unidentified symbol	if the
       symbol is missing some prefix namespace qualifiers.

   Setup
       To use clang-include-fixer two databases	are required. Both can be gen-
       erated with existing tools.

       o Compilation  database.	 Contains  the compiler	commands for any given
	 file in a project and can be generated	by CMake,  see	How  To	 Setup
	 Tooling For LLVM.

       o Symbol	index. Contains	all symbol information in a project to match a
	 given identifier to a header file.

       Ideally	both  databases	  (compile_commands.json   and	 find_all_sym-
       bols_db.yaml)  are  linked into the root	of the source tree they	corre-
       spond to. Then the clang-include-fixer can automatically	pick  them  up
       if  called with a source	file from that tree. Note that by default com-
       pile_commands.json as generated by CMake	does not include header	files,
       so only implementation files can	be handled by tools.

   Creating a Symbol Index From	a Compilation Database
       The  include fixer contains find-all-symbols, a tool to create a	symbol
       database	in YAML	format from a  compilation  database  by  parsing  all
       source  files listed in it. The following list of commands shows	how to
       set up a	database for LLVM, any project built by	 CMake	should	follow
       similar steps.

	  $ cd path/to/llvm-build
	  $ ninja find-all-symbols // build find-all-symbols tool.
	  $ ninja clang-include-fixer // build clang-include-fixer tool.
	  $ ls compile_commands.json # Make sure compile_commands.json exists.
	    compile_commands.json
	  $ path/to/llvm/source/tools/clang/tools/extra/clang-include-fixer/find-all-symbols/tool/run-find-all-symbols.py
	    ...	wait as	clang indexes the code base ...
	  $ ln -s $PWD/find_all_symbols_db.yaml	path/to/llvm/source/ # Link database into the source tree.
	  $ ln -s $PWD/compile_commands.json path/to/llvm/source/ # Also link compilation database if it's not there already.
	  $ cd path/to/llvm/source
	  $ /path/to/clang-include-fixer -db=yaml path/to/file/with/missing/include.cpp
	    Added #include "foo.h"

   Integrate with Vim
       To  run clang-include-fixer on a	potentially unsaved buffer in Vim. Add
       the following key binding to your .vimrc:

	  noremap <leader>cf :pyf path/to/llvm/source/tools/clang/tools/extra/clang-include-fixer/tool/clang-include-fixer.py<cr>

       This enables clang-include-fixer	for NORMAL  and	 VISUAL	 mode.	Change
       _leader_cf to another binding if	you need clang-include-fixer on	a dif-
       ferent key. The _leader_	key is a reference to a	specific  key  defined
       by the mapleader	variable and is	bound to backslash by default.

       Make sure vim can find clang-include-fixer:

       o Add the path to clang-include-fixer to	the PATH environment variable.

       o Or   set   g:clang_include_fixer_path	 in   vimrc:  let  g:clang_in-
	 clude_fixer_path=path/to/clang-include-fixer

       You can customize the number of headers	being  shown  by  setting  let
       g:clang_include_fixer_maximum_suggested_headers=5

       Customized settings in .vimrc:

       o let g:clang_include_fixer_path	= "clang-include-fixer"

	 Set clang-include-fixer binary	file path.

       o let g:clang_include_fixer_maximum_suggested_headers = 3

	 Set the maximum number	of #includes to	show. Default is 3.

       o let g:clang_include_fixer_increment_num = 5

	 Set  the increment number of #includes	to show	every time when	press-
	 ing m.	 Default is 5.

       o let g:clang_include_fixer_jump_to_include = 0

	 Set to	1 if you want to jump to the new inserted #include  line.  De-
	 fault is 0.

       o let g:clang_include_fixer_query_mode =	0

	 Set to	1 if you want to insert	#include for the symbol	under the cur-
	 sor.  Default is 0. Compared to normal	mode, this  mode  won't	 parse
	 the  source  file and only search the sysmbol from database, which is
	 faster	than normal mode.

       See clang-include-fixer.py for more details.

   Integrate with Emacs
       To run clang-include-fixer on a potentially unsaved  buffer  in	Emacs.
       Ensure  that Emacs finds	clang-include-fixer.el by adding the directory
       containing the file  to	the  load-path	and  requiring	the  clang-in-
       clude-fixer in your .emacs:

	  (add-to-list 'load-path "path/to/llvm/source/tools/clang/tools/extra/clang-include-fixer/tool/"
	  (require 'clang-include-fixer)

       Within  Emacs  the  tool	 can be	invoked	with the command M-x clang-in-
       clude-fixer. This will insert the header	that defines the  first	 unde-
       fined  symbol;  if  there is more than one header that would define the
       symbol, the user	is prompted to select one.

       To include the header  that  defines  the  symbol  at  point,  run  M-x
       clang-include-fixer-at-point.

       Make sure Emacs can find	clang-include-fixer:

       o Either	 add  the  parent directory of clang-include-fixer to the PATH
	 environment variable, or customize the	Emacs  user  option  clang-in-
	 clude-fixer-executable	to point to the	file name of the program.

   How it Works
       To  get	the  most  information	out  of	Clang at parse time, clang-in-
       clude-fixer runs	in tandem with the parse and receives  callbacks  from
       Clang's semantic	analysis. In particular	it reuses the existing support
       for typo	corrections. Whenever Clang tries to correct a potential  typo
       it  emits a callback to the include fixer which then looks for a	corre-
       sponding	file. At this point rich lookup	information  is	 still	avail-
       able, which is not available in the AST at a later stage.

       The  identifier that should be typo corrected is	then sent to the data-
       base, if	a header file is returned it is	added as an include  directive
       at the top of the file.

       Currently  clang-include-fixer  only inserts a single include at	a time
       to avoid	getting	caught in follow-up errors. If multiple	#include addi-
       tions  are  desired  the	 program  can  be  rerun  until	a fix-point is
       reached.

MODULARIZE USER'S MANUAL
   Modularize Usage
       modularize [<modularize-options>]  [<module-map>|<include-files-list>]*
       [<front-end-options>...]

       <modularize-options> is a place-holder for options specific to modular-
       ize, which are described	below in Modularize Command Line Options.

       <module-map> specifies the path of a file name for an  existing	module
       map.  The module	map must be well-formed	in terms of syntax. Modularize
       will extract the	header file names from the map.	 Only  normal  headers
       are checked, assuming headers marked "private", "textual", or "exclude"
       are not to be checked as	a top-level include, assuming they either  are
       included	 by  other headers which are checked, or they are not suitable
       for modules.

       <include-files-list> specifies the path of a file name for a file  con-
       taining	the newline-separated list of headers to check with respect to
       each other. Lines beginning with	 '#'  and  empty  lines	 are  ignored.
       Header  file  names  followed by	a colon	and other space-separated file
       names will include those	extra files as dependencies.  The  file	 names
       can  be relative	or full	paths, but must	be on the same line. For exam-
       ple:

	  header1.h
	  header2.h
	  header3.h: header1.h header2.h

       Note that unless	a -prefix (header path)	option is specified, non-abso-
       lute  file paths	in the header list file	will be	relative to the	header
       list file directory. Use	-prefix	to specify a different directory.

       <front-end-options> is a	place-holder for regular Clang front-end argu-
       ments,  which  must  follow the <include-files-list>.  Note that	by de-
       fault, modularize assumes .h files contain C++ source, so  if  you  are
       using  a	 different language, you might need to use a -x	option to tell
       Clang that the header contains another language,	i.e.:  -x c

       Note also that because modularize does not use the  clang  driver,  you
       will  likely need to pass in additional compiler	front-end arguments to
       match those passed in by	default	by the driver.

   Modularize Command Line Options
       -prefix=<header-path>
	      Prepend the given	path to	non-absolute file paths	in the	header
	      list  file.   By	default, headers are assumed to	be relative to
	      the header list file directory. Use -prefix to specify a differ-
	      ent directory.

       -module-map-path=<module-map-path>
	      Generate	a  module map and output it to the given file. See the
	      description in module-map-generation.

       -problem-files-list=<problem-files-list-file-name>
	      For use only with	module map assistant. Input list of files that
	      have  problems  with respect to modules. These will still	be in-
	      cluded in	the generated module map, but will be marked  as  "ex-
	      cluded" headers.

       -root-module=<root-name>
	      Put  modules  generated by the -module-map-path option in	an en-
	      closing module with the given name. See the description in  mod-
	      ule-map-generation.

       -block-check-header-list-only
	      Limit  the  #include-inside-extern-or-namespace-block  check  to
	      only those headers explicitly listed in the header  list.	  This
	      is  a  work-around  for  avoiding	error messages for private in-
	      cludes that purposefully get included inside blocks.

       -no-coverage-check
	      Don't do the coverage check for a	module map.

       -coverage-check-only
	      Only do the coverage check for a module map.

       -display-file-lists
	      Display lists of good files (no compile errors), problem	files,
	      and  a combined list with	problem	files preceded by a '#'.  This
	      can be used to quickly determine which files have	problems.  The
	      latter combined list might be useful in starting to modularize a
	      set of headers. You can start with a full	list of	 headers,  use
	      -display-file-lists  option,  and	 then use the combined list as
	      your intermediate	list,  uncommenting-out	 headers  as  you  fix
	      them.

       modularize  is  a  standalone tool that checks whether a	set of headers
       provides	the consistent definitions required to use modules. For	 exam-
       ple,  it	 detects  whether the same entity (say,	a NULL macro or	size_t
       typedef)	is defined in multiple headers or whether  a  header  produces
       different  definitions  under different circumstances. These conditions
       cause modules built from	the headers to behave poorly,  and  should  be
       fixed before introducing	a module map.

       modularize  also	 has  an assistant mode	option for generating a	module
       map file	based on the provided header list. The	generated  file	 is  a
       functional  module  map that can	be used	as a starting point for	a mod-
       ule.map file.

   Getting Started
       To build	from source:

       1. Read Getting Started with the	LLVM System and	Clang Tools Documenta-
	  tion	for  information on getting sources for	LLVM, Clang, and Clang
	  Extra	Tools.

       2. Getting Started with the LLVM	System and Building  LLVM  with	 CMake
	  give	directions for how to build. With sources all checked out into
	  the right place the LLVM build will  build  Clang  Extra  Tools  and
	  their	dependencies automatically.

	  o If	using  CMake,  you can also use	the modularize target to build
	    just the modularize	tool and its dependencies.

       Before continuing, take a look at ModularizeUsage to see	how to	invoke
       modularize.

   What	Modularize Checks
       Modularize will check for the following:

       o Duplicate global type and variable definitions

       o Duplicate macro definitions

       o Macro	instances,  'defined(macro)',  or  #if,	#elif, #ifdef, #ifndef
	 conditions that evaluate differently in a header

       o #include directives inside 'extern "C/C++" {}'	or  'namespace	(name)
	 {}' blocks

       o Module	 map header coverage completeness (in the case of a module map
	 input only)

       Modularize will do normal C/C++ parsing,	reporting  normal  errors  and
       warnings,  but will also	report special error messages like the follow-
       ing:

	  error: '(symbol)' defined at multiple	locations:
	     (file):(row):(column)
	     (file):(row):(column)

	  error: header	'(file)' has different contents	depending on how it was	included

       The latter might	be followed by messages	like the following:

	  note:	'(symbol)' in (file) at	(row):(column) not always provided

       Checks will also	be performed for macro expansions, defined(macro)  ex-
       pressions, and preprocessor conditional directives that evaluate	incon-
       sistently, and can produce error	messages like the following:

	   (...)/SubHeader.h:11:5:
	  #if SYMBOL ==	1
	      ^
	  error: Macro instance	'SYMBOL' has different values in this header,
		 depending on how it was included.
	    'SYMBOL' expanded to: '1' with respect to these inclusion paths:
	      (...)/Header1.h
		(...)/SubHeader.h
	  (...)/SubHeader.h:3:9:
	  #define SYMBOL 1
		  ^
	  Macro	defined	here.
	    'SYMBOL' expanded to: '2' with respect to these inclusion paths:
	      (...)/Header2.h
		  (...)/SubHeader.h
	  (...)/SubHeader.h:7:9:
	  #define SYMBOL 2
		  ^
	  Macro	defined	here.

       Checks will also	be performed for '#include' directives that are	nested
       inside  'extern	"C/C++"	 {}'  or 'namespace (name) {}' blocks, and can
       produce error message like the following:

	  IncludeInExtern.h:2:3:
	  #include "Empty.h"
	  ^
	  error: Include directive within extern "C" {}.
	  IncludeInExtern.h:1:1:
	  extern "C" {
	  ^
	  The "extern "C" {}" block is here.

   Module Map Coverage Check
       The coverage check uses the Clang library to read and parse the	module
       map  file.  Starting  at	the module map file directory, or just the in-
       clude paths, if specified, it will collect the names of all  the	 files
       it considers headers (no	extension, .h, or .inc--if you need more, mod-
       ify the isHeader	function). It then compares the	headers	against	 those
       referenced  in  the  module map,	either explicitly named, or implicitly
       named via an umbrella directory or umbrella file, as parsed by the Mod-
       uleMap  object.	 If headers are	found which are	not referenced or cov-
       ered by an umbrella directory or	file, warning messages	will  be  pro-
       duced,  and this	program	will return an error code of 1.	If no problems
       are found, an error code	of 0 is	returned.

       Note that in the	case of	umbrella headers, this tool invokes  the  com-
       piler to	preprocess the file, and uses a	callback to collect the	header
       files included by the umbrella header or	any of its nested includes. If
       any  front end options are needed for these compiler invocations, these
       can be included on the command line after the module map	file argument.

       Warning message have the	form:
	  warning: module.modulemap does not account for file: Level3A.h

       Note that for the case of the module map	referencing a file  that  does
       not  exist,  the	 module	 map parser in Clang will (at the time of this
       writing)	display	an error message.

       To limit	the checks modularize does to just  the	 module	 map  coverage
       check, use the -coverage-check-only option.

       For example:

	  modularize -coverage-check-only module.modulemap

   Module Map Generation
       If  you specify the -module-map-path=<module map	file>, modularize will
       output a	module map based on the	input header list.  A module  will  be
       created	for  each  header. Also, if the	header in the header list is a
       partial path, a nested module hierarchy will be created in which	a mod-
       ule will	be created for each subdirectory component in the header path,
       with the	header itself represented by the innermost  module.  If	 other
       headers	use  the  same	subdirectories,	they will be enclosed in these
       same modules also.

       For example, for	the header list:

	  SomeTypes.h
	  SomeDecls.h
	  SubModule1/Header1.h
	  SubModule1/Header2.h
	  SubModule2/Header3.h
	  SubModule2/Header4.h
	  SubModule2.h

       The following module map	will be	generated:

	  // Output/NoProblemsAssistant.txt
	  // Generated by: modularize -module-map-path=Output/NoProblemsAssistant.txt \
	       -root-module=Root NoProblemsAssistant.modularize

	  module SomeTypes {
	    header "SomeTypes.h"
	    export *
	  }
	  module SomeDecls {
	    header "SomeDecls.h"
	    export *
	  }
	  module SubModule1 {
	    module Header1 {
	      header "SubModule1/Header1.h"
	      export *
	    }
	    module Header2 {
	      header "SubModule1/Header2.h"
	      export *
	    }
	  }
	  module SubModule2 {
	    module Header3 {
	      header "SubModule2/Header3.h"
	      export *
	    }
	    module Header4 {
	      header "SubModule2/Header4.h"
	      export *
	    }
	    header "SubModule2.h"
	    export *
	  }

       An optional -root-module=<root-name> option can be used to cause	a root
       module to be created which encloses all the modules.

       An  optional -problem-files-list=<problem-file-name> can	be used	to in-
       put a list of files to be excluded, perhaps  as	a  temporary  stop-gap
       measure until problem headers can be fixed.

       For example, with the same header list from above:

	  // Output/NoProblemsAssistant.txt
	  // Generated by: modularize -module-map-path=Output/NoProblemsAssistant.txt \
	       -root-module=Root NoProblemsAssistant.modularize

	  module Root {
	    module SomeTypes {
	      header "SomeTypes.h"
	      export *
	    }
	    module SomeDecls {
	      header "SomeDecls.h"
	      export *
	    }
	    module SubModule1 {
	      module Header1 {
		header "SubModule1/Header1.h"
		export *
	      }
	      module Header2 {
		header "SubModule1/Header2.h"
		export *
	      }
	    }
	    module SubModule2 {
	      module Header3 {
		header "SubModule2/Header3.h"
		export *
	      }
	      module Header4 {
		header "SubModule2/Header4.h"
		export *
	      }
	      header "SubModule2.h"
	      export *
	    }
	  }

       Note  that  headers  with dependents will be ignored with a warning, as
       the Clang module	mechanism doesn't support headers the  rely  on	 other
       headers to be included first.

       The module map format defines some keywords which can't be used in mod-
       ule names. If a header has one of these names, an underscore ('_') will
       be  prepended to	the name. For example, if the header name is header.h,
       because header is a keyword, the	module name will be  _header.	For  a
       list of the module map keywords,	please see: Lexical structure

PP-TRACE USER'S	MANUAL
       pp-trace	 is  a standalone tool that traces preprocessor	activity. It's
       also used as a test of Clang's PPCallbacks interface.  It runs a	 given
       source  file through the	Clang preprocessor, displaying selected	infor-
       mation from callback functions overridden in a PPCallbacks  derivation.
       The output is in	a high-level YAML format, described in pp-trace	Output
       Format.

   pp-trace Usage
   Command Line	Format
       pp-trace	[<pp-trace-options>] <source-file> [-- <front-end-options>]

       <pp-trace-options> is a place-holder for	options	specific to  pp-trace,
       which are described below in Command Line Options.

       <source-file>  specifies	 the source file to run	through	the preproces-
       sor.

       <front-end-options> is a	place-holder for regular  Clang	 Compiler  Op-
       tions, which must follow	the <source-file>.

   Command Line	Options
       -callbacks <comma-separated-globs>
	      This option specifies a comma-separated list of globs describing
	      the list of callbacks that should	be traced. Globs are processed
	      in order of appearance.  Positive	globs add matched callbacks to
	      the set, netative	globs  (those  with  the  '-'  prefix)	remove
	      callacks from the	set.

	      o	FileChanged

	      o	FileSkipped

	      o	FileNotFound

	      o	InclusionDirective

	      o	moduleImport

	      o	EndOfMainFile

	      o	Ident

	      o	PragmaDirective

	      o	PragmaComment

	      o	PragmaDetectMismatch

	      o	PragmaDebug

	      o	PragmaMessage

	      o	PragmaDiagnosticPush

	      o	PragmaDiagnosticPop

	      o	PragmaDiagnostic

	      o	PragmaOpenCLExtension

	      o	PragmaWarning

	      o	PragmaWarningPush

	      o	PragmaWarningPop

	      o	MacroExpands

	      o	MacroDefined

	      o	MacroUndefined

	      o	Defined

	      o	SourceRangeSkipped

	      o	If

	      o	Elif

	      o	Ifdef

	      o	Ifndef

	      o	Else

	      o	Endif

       -output <output-file>
	      By  default,  pp-trace  outputs the trace	information to stdout.
	      Use this option to output	the trace information to a file.

   pp-trace Output Format
       The pp-trace output is formatted	as  YAML.  See	https://yaml.org/  for
       general	YAML  information.  It's arranged as a sequence	of information
       about the callback call,	including the callback name and	 argument  in-
       formation, for example::

	  ---
	  - Callback: Name
	    Argument1: Value1
	    Argument2: Value2
	  (etc.)
	  ...

       With real data::

	  ---
	  - Callback: FileChanged
	    Loc: "c:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-include.cpp:1:1"
	    Reason: EnterFile
	    FileType: C_User
	    PrevFID: (invalid)
	    (etc.)
	  - Callback: FileChanged
	    Loc: "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-include.cpp:5:1"
	    Reason: ExitFile
	    FileType: C_User
	    PrevFID: "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/Input/Level1B.h"
	  - Callback: EndOfMainFile
	  ...

       In  all	but  one case (MacroDirective) the "Argument" scalars have the
       same name as the	argument in  the  corresponding	 PPCallbacks  callback
       function.

   Callback Details
       The  following  sections	describe the pupose and	output format for each
       callback.

       Click on	the callback name in the section heading to  see  the  Doxygen
       documentation for the callback.

       The  argument descriptions table	describes the callback argument	infor-
       mation displayed.

       The Argument Name field in most (but not	all) cases is the same name as
       the callback function parameter.

       The  Argument Value Syntax field	describes the values that will be dis-
       played for the argument value. It uses an ad  hoc  representation  that
       mixes  literal and symbolic representations. Enumeration	member symbols
       are shown as the	actual enum member in a	(member1|member2|...) form.  A
       name  in	 parentheses  can  either represent a place holder for the de-
       scribed value, or confusingly, it might be a literal, such  as  (null),
       for  a  null pointer.  Locations	are shown as quoted only to avoid con-
       fusing the documentation	generator.

       The Clang C++ Type field	is the type from the callback function	decla-
       ration.

       The description describes the argument or what is displayed for it.

       Note  that  in some cases, such as when a structure pointer is an argu-
       ment value, only	some key member	or members are shown to	represent  the
       value, instead of trying	to display all members of the structure.

   FileChanged Callback
       FileChanged  is	called	when  the preprocessor enters or exits a file,
       both the	top level file being compiled, as well as any #include	direc-
       tives.  It will also be called as a result of a system header pragma or
       in internal renaming of a file.

       Argument	descriptions:

    +--------------+-----------------------+------------------+------------------+
    |Argument Name | Argument	Value	   | Clang C++ Type   |	Description	 |
    |		   | Syntax		   |		      |			 |
    +--------------+-----------------------+------------------+------------------+
    |Loc	   | "(file):(line):(col)" | SourceLocation   |	The location  of |
    |		   |			   |		      |	the directive.	 |
    +--------------+-----------------------+------------------+------------------+
    |Reason	   | (EnterFile|Exit-	   | PPCall-	      |	Reason	     for |
    |		   | File|SystemHeader-	   | backs::FileChan- |	change.		 |
    |		   | Pragma|RenameFile)	   | geReason	      |			 |
    +--------------+-----------------------+------------------+------------------+
    |FileType	   | (C_User|C_Sys-	   | SrcMgr::Charac-  |	Include	type.	 |
    |		   | tem|C_ExternCSystem)  | teristicKind     |			 |
    +--------------+-----------------------+------------------+------------------+
    |PrevFID	   | ((file)|(invalid))	   | FileID	      |	Previous   file, |
    |		   |			   |		      |	if any.		 |
    +--------------+-----------------------+------------------+------------------+

       Example::

	  - Callback: FileChanged
	    Loc: "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-include.cpp:1:1"
	    Reason: EnterFile
	    FileType: C_User
	    PrevFID: (invalid)

   FileSkipped Callback
       FileSkipped  is	called	when a source file is skipped as the result of
       header guard optimization.

       Argument	descriptions:

       +--------------+------------------+-----------------+------------------+
       |Argument Name |	Argument   Value | Clang C++ Type  | Description      |
       |	      |	Syntax		 |		   |		      |
       +--------------+------------------+-----------------+------------------+
       |ParentFile    |	("(file)"     or | const FileEntry | The  file	 that |
       |	      |	(null))		 |		   | #included	  the |
       |	      |			 |		   | skipped file.    |
       +--------------+------------------+-----------------+------------------+
       |FilenameTok   |	(token)		 | const Token	   | The   token   in |
       |	      |			 |		   | ParentFile	 that |
       |	      |			 |		   | indicates	  the |
       |	      |			 |		   | skipped file.    |
       +--------------+------------------+-----------------+------------------+
       |FileType      |	(C_User|C_Sys-	 | SrcMgr::Charac- | The file type.   |
       |	      |	tem|C_ExternC-	 | teristicKind	   |		      |
       |	      |	System)		 |		   |		      |
       +--------------+------------------+-----------------+------------------+

       Example::

	  - Callback: FileSkipped
	    ParentFile:	"/path/filename.h"
	    FilenameTok: "filename.h"
	    FileType: C_User

   FileNotFound	Callback
       FileNotFound is	called	when  an  inclusion  directive	results	 in  a
       file-not-found error.

       Argument	descriptions:

       +--------------+------------------+----------------+------------------+
       |Argument Name |	Argument   Value | Clang C++ Type | Description	     |
       |	      |	Syntax		 |		  |		     |
       +--------------+------------------+----------------+------------------+
       |FileName      |	"(file)"	 | StringRef	  | The	name of	 the |
       |	      |			 |		  | file  being	 in- |
       |	      |			 |		  | cluded, as writ- |
       |	      |			 |		  | ten	   in	 the |
       |	      |			 |		  | source code.     |
       +--------------+------------------+----------------+------------------+
       |RecoveryPath  |	(path)		 | SmallVec-	  | If	this  client |
       |	      |			 | torImpl<char>  | indicates	that |
       |	      |			 |		  | it	can  recover |
       |	      |			 |		  | from this  miss- |
       |	      |			 |		  | ing	  file,	 the |
       |	      |			 |		  | client    should |
       |	      |			 |		  | set	 this  as an |
       |	      |			 |		  | additional	     |
       |	      |			 |		  | header    search |
       |	      |			 |		  | patch.	     |
       +--------------+------------------+----------------+------------------+

       Example::

	  - Callback: FileNotFound
	    FileName: "/path/filename.h"
	    RecoveryPath:

   InclusionDirective Callback
       InclusionDirective is called when an inclusion directive	 of  any  kind
       (#include</code>,  #import</code>, etc.)	has been processed, regardless
       of whether the inclusion	will actually result in	an inclusion.

       Argument	descriptions:

     +--------------+-----------------------+-----------------+------------------+
     |Argument Name | Argument	 Value	    | Clang C++	Type  |	Description	 |
     |		    | Syntax		    |		      |			 |
     +--------------+-----------------------+-----------------+------------------+
     |HashLoc	    | "(file):(line):(col)" | SourceLocation  |	The location  of |
     |		    |			    |		      |	the   '#'   that |
     |		    |			    |		      |	starts	the  in- |
     |		    |			    |		      |	clusion	  direc- |
     |		    |			    |		      |	tive.		 |
     +--------------+-----------------------+-----------------+------------------+
     |IncludeTok    | (token)		    | const Token     |	The  token  that |
     |		    |			    |		      |	indicates    the |
     |		    |			    |		      |	kind  of  inclu- |
     |		    |			    |		      |	sion  directive, |
     |		    |			    |		      |	e.g.,  'include' |
     |		    |			    |		      |	or 'import'.	 |
     +--------------+-----------------------+-----------------+------------------+
     |FileName	    | "(file)"		    | StringRef	      |	The  name of the |
     |		    |			    |		      |	file  being  in- |
     |		    |			    |		      |	cluded,	as writ- |
     |		    |			    |		      |	ten    in    the |
     |		    |			    |		      |	source code.	 |
     +--------------+-----------------------+-----------------+------------------+

     |IsAngled	    | (true|false)	    | bool	      |	Whether	the file |
     |		    |			    |		      |	name   was   en- |
     |		    |			    |		      |	closed	in angle |
     |		    |			    |		      |	brackets; other- |
     |		    |			    |		      |	wise, it was en- |
     |		    |			    |		      |	closed	      in |
     |		    |			    |		      |	quotes.		 |
     +--------------+-----------------------+-----------------+------------------+
     |FilenameRange | "(file)"		    | CharSourceRange |	The    character |
     |		    |			    |		      |	range	of   the |
     |		    |			    |		      |	quotes	or angle |
     |		    |			    |		      |	brackets for the |
     |		    |			    |		      |	written	    file |
     |		    |			    |		      |	name.		 |
     +--------------+-----------------------+-----------------+------------------+
     |File	    | "(file)"		    | const FileEntry |	The actual  file |
     |		    |			    |		      |	that  may be in- |
     |		    |			    |		      |	cluded	by  this |
     |		    |			    |		      |	inclusion direc- |
     |		    |			    |		      |	tive.		 |
     +--------------+-----------------------+-----------------+------------------+
     |SearchPath    | "(path)"		    | StringRef	      |	Contains     the |
     |		    |			    |		      |	search	    path |
     |		    |			    |		      |	which  was  used |
     |		    |			    |		      |	to find	the file |
     |		    |			    |		      |	in the file sys- |
     |		    |			    |		      |	tem.		 |
     +--------------+-----------------------+-----------------+------------------+
     |RelativePath  | "(path)"		    | StringRef	      |	The  path  rela- |
     |		    |			    |		      |	tive to	 Search- |
     |		    |			    |		      |	Path,  at  which |
     |		    |			    |		      |	the include file |
     |		    |			    |		      |	was found.	 |
     +--------------+-----------------------+-----------------+------------------+
     |Imported	    | ((module		    | const Module    |	The	 module, |
     |		    | name)|(null))	    |		      |	whenever  an in- |
     |		    |			    |		      |	clusion	  direc- |
     |		    |			    |		      |	tive  was  auto- |
     |		    |			    |		      |	matically turned |
     |		    |			    |		      |	into   a  module |
     |		    |			    |		      |	import	or  null |
     |		    |			    |		      |	otherwise.	 |
     +--------------+-----------------------+-----------------+------------------+

       Example::

	  - Callback: InclusionDirective
	    IncludeTok:	include
	    FileName: "Input/Level1B.h"
	    IsAngled: false
	    FilenameRange: "Input/Level1B.h"
	    File: "D:/Clang/llvmnewmod/tools/clang/tools/extra/test/pp-trace/Input/Level1B.h"
	    SearchPath:	"D:/Clang/llvmnewmod/tools/clang/tools/extra/test/pp-trace"
	    RelativePath: "Input/Level1B.h"
	    Imported: (null)

   moduleImport	Callback
       moduleImport is called when there was an	explicit module-import syntax.

       Argument	descriptions:

     +--------------+-----------------------+----------------+------------------+
     |Argument Name | Argument	 Value	    | Clang C++	Type | Description	|
     |		    | Syntax		    |		     |			|
     +--------------+-----------------------+----------------+------------------+
     |ImportLoc	    | "(file):(line):(col)" | SourceLocation | The  location of	|
     |		    |			    |		     | import directive	|
     |		    |			    |		     | token.		|
     +--------------+-----------------------+----------------+------------------+
     |Path	    | "(path)"		    | ModuleIdPath   | The  identifiers	|
     |		    |			    |		     | (and their loca-	|
     |		    |			    |		     | tions)	of  the	|
     |		    |			    |		     | module "path".	|
     +--------------+-----------------------+----------------+------------------+
     |Imported	    | ((module		    | const Module   | The     imported	|
     |		    | name)|(null))	    |		     | module;	can  be	|
     |		    |			    |		     | null  if	import-	|
     |		    |			    |		     | ing failed.	|
     +--------------+-----------------------+----------------+------------------+

       Example::

	  - Callback: moduleImport
	    ImportLoc: "d:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-modules.cpp:4:2"
	    Path: [{Name: Level1B, Loc:	"d:/Clang/llvmnewmod/tools/clang/tools/extra/test/pp-trace/pp-trace-modules.cpp:4:9"}, {Name: Level2B, Loc: "d:/Clang/llvmnewmod/tools/clang/tools/extra/test/pp-trace/pp-trace-modules.cpp:4:17"}]
	    Imported: Level2B

   EndOfMainFile Callback
       EndOfMainFile is	called when the	end of the main	file is	reached.

       Argument	descriptions:

	 +---------------+------------------+----------------+-------------+
	 |Argument Name	 | Argument   Value | Clang C++	Type | Description |
	 |		 | Syntax	    |		     |		   |
	 +---------------+------------------+----------------+-------------+
	 |(no arguments) |		    |		     |		   |
	 +---------------+------------------+----------------+-------------+

       Example::

	  - Callback: EndOfMainFile

   Ident Callback
       Ident is	called when a #ident or	#sccs directive	is read.

       Argument	descriptions:

     +--------------+-----------------------+----------------+------------------+
     |Argument Name | Argument	 Value	    | Clang C++	Type | Description	|
     |		    | Syntax		    |		     |			|
     +--------------+-----------------------+----------------+------------------+
     |Loc	    | "(file):(line):(col)" | SourceLocation | The  location of	|
     |		    |			    |		     | the directive.	|
     +--------------+-----------------------+----------------+------------------+
     |str	    | (name)		    | const	     | The  text of the	|
     |		    |			    | std::string    | directive.	|
     +--------------+-----------------------+----------------+------------------+

       Example::

	  - Callback: Ident
	    Loc: "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-ident.cpp:3:1"
	    str: "$Id$"

   PragmaDirective Callback
       PragmaDirective is called when start reading any	pragma directive.

       Argument	descriptions:

+--------------+----------------------------------+-----------------+------------------+
|Argument Name | Argument   Value		  | Clang C++ Type  | Description      |
|	       | Syntax				  |		    |		       |
+--------------+----------------------------------+-----------------+------------------+
|Loc	       | "(file):(line):(col)"		  | SourceLocation  | The location  of |
|	       |				  |		    | the directive.   |
+--------------+----------------------------------+-----------------+------------------+
|Introducer    | (PIK_Hash-			  | PragmaIntroduc- | The type of  the |
|	       | Pragma|PIK__Pragma|PIK___pragma) | erKind	    | pragma	direc- |
|	       |				  |		    | tive.	       |
+--------------+----------------------------------+-----------------+------------------+

       Example::

	  - Callback: PragmaDirective
	    Loc: "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-pragma.cpp:3:1"
	    Introducer:	PIK_HashPragma

   PragmaComment Callback
       PragmaComment is	called when a #pragma comment directive	is read.

       Argument	descriptions:

    +--------------+-----------------------+------------------+------------------+
    |Argument Name | Argument	Value	   | Clang C++ Type   |	Description	 |
    |		   | Syntax		   |		      |			 |
    +--------------+-----------------------+------------------+------------------+
    |Loc	   | "(file):(line):(col)" | SourceLocation   |	The location  of |
    |		   |			   |		      |	the directive.	 |
    +--------------+-----------------------+------------------+------------------+
    |Kind	   | ((name)|(null))	   | const    Identi- |	The comment kind |
    |		   |			   | fierInfo	      |	symbol.		 |
    +--------------+-----------------------+------------------+------------------+
    |Str	   | (message directive)   | const	      |	The comment mes- |
    |		   |			   | std::string      |	sage directive.	 |
    +--------------+-----------------------+------------------+------------------+

       Example::

	  - Callback: PragmaComment
	    Loc: "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-pragma.cpp:3:1"
	    Kind: library
	    Str: kernel32.lib

   PragmaDetectMismatch	Callback
       PragmaDetectMismatch is called when a #pragma detect_mismatch directive
       is read.

       Argument	descriptions:

     +--------------+-----------------------+----------------+------------------+
     |Argument Name | Argument	 Value	    | Clang C++	Type | Description	|
     |		    | Syntax		    |		     |			|
     +--------------+-----------------------+----------------+------------------+

     |Loc	    | "(file):(line):(col)" | SourceLocation | The location  of	|
     |		    |			    |		     | the directive.	|
     +--------------+-----------------------+----------------+------------------+
     |Name	    | "(name)"		    | const	     | The name.	|
     |		    |			    | std::string    |			|
     +--------------+-----------------------+----------------+------------------+
     |Value	    | (string)		    | const	     | The value.	|
     |		    |			    | std::string    |			|
     +--------------+-----------------------+----------------+------------------+

       Example::

	  - Callback: PragmaDetectMismatch
	    Loc: "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-pragma.cpp:3:1"
	    Name: name
	    Value: value

   PragmaDebug Callback
       PragmaDebug is called when a #pragma clang __debug directive is read.

       Argument	descriptions:

     +--------------+-----------------------+----------------+------------------+
     |Argument Name | Argument	 Value	    | Clang C++	Type | Description	|
     |		    | Syntax		    |		     |			|
     +--------------+-----------------------+----------------+------------------+
     |Loc	    | "(file):(line):(col)" | SourceLocation | The  location of	|
     |		    |			    |		     | the directive.	|
     +--------------+-----------------------+----------------+------------------+
     |DebugType	    | (string)		    | StringRef	     | Indicates   type	|
     |		    |			    |		     | of   debug  mes-	|
     |		    |			    |		     | sage.		|
     +--------------+-----------------------+----------------+------------------+

       Example::

	  - Callback: PragmaDebug
	    Loc: "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-pragma.cpp:3:1"
	    DebugType: warning

   PragmaMessage Callback
       PragmaMessage is	called when a #pragma message directive	is read.

       Argument	descriptions:

     +--------------+-----------------------+----------------+------------------+
     |Argument Name | Argument	 Value	    | Clang C++	Type | Description	|
     |		    | Syntax		    |		     |			|
     +--------------+-----------------------+----------------+------------------+
     |Loc	    | "(file):(line):(col)" | SourceLocation | The location  of	|
     |		    |			    |		     | the directive.	|
     +--------------+-----------------------+----------------+------------------+
     |Namespace	    | (name)		    | StringRef	     | The namespace of	|
     |		    |			    |		     | the message  di-	|
     |		    |			    |		     | rective.		|
     +--------------+-----------------------+----------------+------------------+
     |Kind	    | (PMK_Mes-		    | PPCall-	     | The  type of the	|
     |		    | sage|PMK_Warn-	    | backs::Prag-   | message	 direc-	|
     |		    | ing|PMK_Error)	    | maMessageKind  | tive.		|
     +--------------+-----------------------+----------------+------------------+
     |Str	    | (string)		    | StringRef	     | The  text of the	|
     |		    |			    |		     | message	 direc-	|
     |		    |			    |		     | tive.		|
     +--------------+-----------------------+----------------+------------------+

       Example::

	  - Callback: PragmaMessage
	    Loc: "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-pragma.cpp:3:1"
	    Namespace: "GCC"
	    Kind: PMK_Message
	    Str: The message text.

   PragmaDiagnosticPush	Callback
       PragmaDiagnosticPush is called when a #pragma gcc dianostic push	direc-
       tive is read.

       Argument	descriptions:

     +--------------+-----------------------+----------------+------------------+
     |Argument Name | Argument	 Value	    | Clang C++	Type | Description	|
     |		    | Syntax		    |		     |			|
     +--------------+-----------------------+----------------+------------------+
     |Loc	    | "(file):(line):(col)" | SourceLocation | The location  of	|
     |		    |			    |		     | the directive.	|
     +--------------+-----------------------+----------------+------------------+
     |Namespace	    | (name)		    | StringRef	     | Namespace name.	|
     +--------------+-----------------------+----------------+------------------+

       Example::

	  - Callback: PragmaDiagnosticPush
	    Loc: "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-pragma.cpp:3:1"
	    Namespace: "GCC"

   PragmaDiagnosticPop Callback
       PragmaDiagnosticPop  is	called when a #pragma gcc dianostic pop	direc-
       tive is read.

       Argument	descriptions:

     +--------------+-----------------------+----------------+------------------+
     |Argument Name | Argument	 Value	    | Clang C++	Type | Description	|
     |		    | Syntax		    |		     |			|
     +--------------+-----------------------+----------------+------------------+
     |Loc	    | "(file):(line):(col)" | SourceLocation | The location  of	|
     |		    |			    |		     | the directive.	|
     +--------------+-----------------------+----------------+------------------+
     |Namespace	    | (name)		    | StringRef	     | Namespace name.	|
     +--------------+-----------------------+----------------+------------------+

       Example::

	  - Callback: PragmaDiagnosticPop
	    Loc: "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-pragma.cpp:3:1"
	    Namespace: "GCC"

   PragmaDiagnostic Callback
       PragmaDiagnostic	 is  called  when a #pragma gcc	dianostic directive is
       read.

       Argument	descriptions:

     +--------------+-----------------------+----------------+------------------+
     |Argument Name | Argument	 Value	    | Clang C++	Type | Description	|
     |		    | Syntax		    |		     |			|
     +--------------+-----------------------+----------------+------------------+
     |Loc	    | "(file):(line):(col)" | SourceLocation | The location  of	|
     |		    |			    |		     | the directive.	|
     +--------------+-----------------------+----------------+------------------+
     |Namespace	    | (name)		    | StringRef	     | Namespace name.	|
     +--------------+-----------------------+----------------+------------------+
     |mapping	    | (0|MAP_IG-	    | diag::Severity | Mapping type.	|
     |		    | NORE|MAP_WARN-	    |		     |			|
     |		    | ING|MAP_ERROR|MAP_FA- |		     |			|
     |		    | TAL)		    |		     |			|
     +--------------+-----------------------+----------------+------------------+
     |Str	    | (string)		    | StringRef	     | Warning/error	|
     |		    |			    |		     | name.		|
     +--------------+-----------------------+----------------+------------------+

       Example::

	  - Callback: PragmaDiagnostic
	    Loc: "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-pragma.cpp:3:1"
	    Namespace: "GCC"
	    mapping: MAP_WARNING
	    Str: WarningName

   PragmaOpenCLExtension Callback
       PragmaOpenCLExtension  is  called  when OpenCL extension	is either dis-
       abled or	enabled	with a pragma.

       Argument	descriptions:

    +--------------+-----------------------+------------------+------------------+
    |Argument Name | Argument	Value	   | Clang C++ Type   |	Description	 |
    |		   | Syntax		   |		      |			 |
    +--------------+-----------------------+------------------+------------------+
    |NameLoc	   | "(file):(line):(col)" | SourceLocation   |	The location  of |
    |		   |			   |		      |	the name.	 |
    +--------------+-----------------------+------------------+------------------+
    |Name	   | (name)		   | const    Identi- |	Name symbol.	 |
    |		   |			   | fierInfo	      |			 |
    +--------------+-----------------------+------------------+------------------+
    |StateLoc	   | "(file):(line):(col)" | SourceLocation   |	The location  of |
    |		   |			   |		      |	the state.	 |
    +--------------+-----------------------+------------------+------------------+
    |State	   | (1|0)		   | unsigned	      |	Enabled/disabled |
    |		   |			   |		      |	state.		 |
    +--------------+-----------------------+------------------+------------------+

       Example::

	  - Callback: PragmaOpenCLExtension
	    NameLoc: "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-pragma.cpp:3:10"
	    Name: Name
	    StateLoc: "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-pragma.cpp:3:18"
	    State: 1

   PragmaWarning Callback
       PragmaWarning is	called when a #pragma warning directive	is read.

       Argument	descriptions:

     +--------------+-----------------------+----------------+------------------+
     |Argument Name | Argument	 Value	    | Clang C++	Type | Description	|
     |		    | Syntax		    |		     |			|
     +--------------+-----------------------+----------------+------------------+
     |Loc	    | "(file):(line):(col)" | SourceLocation | The location  of	|
     |		    |			    |		     | the directive.	|
     +--------------+-----------------------+----------------+------------------+
     |WarningSpec   | (string)		    | StringRef	     | The	warning	|
     |		    |			    |		     | specifier.	|
     +--------------+-----------------------+----------------+------------------+
     |Ids	    | [(number)[, ...]]	    | ArrayRef<int>  | The warning num-	|
     |		    |			    |		     | bers.		|
     +--------------+-----------------------+----------------+------------------+

       Example::

	  - Callback: PragmaWarning
	    Loc: "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-pragma.cpp:3:1"
	    WarningSpec: disable
	    Ids: 1,2,3

   PragmaWarningPush Callback
       PragmaWarningPush  is  called when a #pragma warning(push) directive is
       read.

       Argument	descriptions:

     +--------------+-----------------------+----------------+------------------+
     |Argument Name | Argument	 Value	    | Clang C++	Type | Description	|
     |		    | Syntax		    |		     |			|
     +--------------+-----------------------+----------------+------------------+
     |Loc	    | "(file):(line):(col)" | SourceLocation | The location  of	|
     |		    |			    |		     | the directive.	|
     +--------------+-----------------------+----------------+------------------+
     |Level	    | (number)		    | int	     | Warning level.	|
     +--------------+-----------------------+----------------+------------------+

       Example::

	  - Callback: PragmaWarningPush
	    Loc: "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-pragma.cpp:3:1"
	    Level: 1

   PragmaWarningPop Callback
       PragmaWarningPop	 is  called  when  a #pragma warning(pop) directive is
       read.

       Argument	descriptions:

     +--------------+-----------------------+----------------+------------------+
     |Argument Name | Argument	 Value	    | Clang C++	Type | Description	|
     |		    | Syntax		    |		     |			|
     +--------------+-----------------------+----------------+------------------+
     |Loc	    | "(file):(line):(col)" | SourceLocation | The location  of	|
     |		    |			    |		     | the directive.	|
     +--------------+-----------------------+----------------+------------------+

       Example::

	  - Callback: PragmaWarningPop
	    Loc: "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-pragma.cpp:3:1"

   MacroExpands	Callback
       MacroExpands  is	 called	 when  ::HandleMacroExpandedIdentifier	when a
       macro invocation	is found.

       Argument	descriptions:

   +---------------+-------------------------+------------------+------------------+
   |Argument Name  | Argument	Value	     | Clang C++ Type	| Description	   |
   |		   | Syntax		     |			|		   |
   +---------------+-------------------------+------------------+------------------+
   |MacroNameTok   | (token)		     | const Token	| The  macro  name |
   |		   |			     |			| token.	   |
   +---------------+-------------------------+------------------+------------------+
   |MacroDirective | (MD_De-		     | const   MacroDi-	| The	kind	of |
   |		   | fine|MD_Unde-	     | rective		| macro	 directive |
   |		   | fine|MD_Visibil-	     |			| from	       the |
   |		   | ity)		     |			| MacroDirective   |
   |		   |			     |			| structure.	   |
   +---------------+-------------------------+------------------+------------------+
   |Range	   | ["(file):(line):(col)", | SourceRange	| The source range |
   |		   | "(file):(line):(col)"]  |			| for  the  expan- |
   |		   |			     |			| sion.		   |
   +---------------+-------------------------+------------------+------------------+

   |Args	   | [(name)|(number)|<(to-  | const MacroArgs	| The argument to- |
   |		   | ken name)>[, ...]]	     |			| kens.	Names  and |
   |		   |			     |			| numbers are lit- |
   |		   |			     |			| eral,	everything |
   |		   |			     |			| else	is  of the |
   |		   |			     |			| form '<'  token- |
   |		   |			     |			| Name '>'.	   |
   +---------------+-------------------------+------------------+------------------+

       Example::

	  - Callback: MacroExpands
	    MacroNameTok: X_IMPL
	    MacroDirective: MD_Define
	    Range: [(nonfile), (nonfile)]
	    Args: [a <plus> y, b]

   MacroDefined	Callback
       MacroDefined is called when a macro definition is seen.

       Argument	descriptions:

      +---------------+------------------+------------------+------------------+
      |Argument	Name  |	Argument   Value | Clang C++ Type   | Description      |
      |		      |	Syntax		 |		    |		       |
      +---------------+------------------+------------------+------------------+
      |MacroNameTok   |	(token)		 | const Token	    | The  macro  name |
      |		      |			 |		    | token.	       |
      +---------------+------------------+------------------+------------------+
      |MacroDirective |	(MD_De-		 | const   MacroDi- | The    kind   of |
      |		      |	fine|MD_Unde-	 | rective	    | macro  directive |
      |		      |	fine|MD_Visibil- |		    | from	   the |
      |		      |	ity)		 |		    | MacroDirective   |
      |		      |			 |		    | structure.       |
      +---------------+------------------+------------------+------------------+

       Example::

	  - Callback: MacroDefined
	    MacroNameTok: X_IMPL
	    MacroDirective: MD_Define

   MacroUndefined Callback
       MacroUndefined is called	when a macro #undef is seen.

       Argument	descriptions:

      +---------------+------------------+------------------+------------------+
      |Argument	Name  |	Argument   Value | Clang C++ Type   | Description      |
      |		      |	Syntax		 |		    |		       |
      +---------------+------------------+------------------+------------------+
      |MacroNameTok   |	(token)		 | const Token	    | The  macro  name |
      |		      |			 |		    | token.	       |
      +---------------+------------------+------------------+------------------+
      |MacroDirective |	(MD_De-		 | const   MacroDi- | The    kind   of |
      |		      |	fine|MD_Unde-	 | rective	    | macro  directive |
      |		      |	fine|MD_Visibil- |		    | from	   the |
      |		      |	ity)		 |		    | MacroDirective   |
      |		      |			 |		    | structure.       |
      +---------------+------------------+------------------+------------------+

       Example::

	  - Callback: MacroUndefined
	    MacroNameTok: X_IMPL
	    MacroDirective: MD_Define

   Defined Callback
       Defined is called when the 'defined' operator is	seen.

       Argument	descriptions:

   +---------------+-------------------------+------------------+------------------+
   |Argument Name  | Argument	Value	     | Clang C++ Type	| Description	   |
   |		   | Syntax		     |			|		   |
   +---------------+-------------------------+------------------+------------------+
   |MacroNameTok   | (token)		     | const Token	| The  macro  name |
   |		   |			     |			| token.	   |
   +---------------+-------------------------+------------------+------------------+
   |MacroDirective | (MD_De-		     | const   MacroDi-	| The	 kind	of |
   |		   | fine|MD_Unde-	     | rective		| macro	 directive |
   |		   | fine|MD_Visibil-	     |			| from	       the |
   |		   | ity)		     |			| MacroDirective   |
   |		   |			     |			| structure.	   |
   +---------------+-------------------------+------------------+------------------+
   |Range	   | ["(file):(line):(col)", | SourceRange	| The source range |
   |		   | "(file):(line):(col)"]  |			| for  the  direc- |
   |		   |			     |			| tive.		   |
   +---------------+-------------------------+------------------+------------------+

       Example::

	  - Callback: Defined
	    MacroNameTok: MACRO
	    MacroDirective: (null)
	    Range: ["D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-macro.cpp:8:5", "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-macro.cpp:8:19"]

   SourceRangeSkipped Callback
       SourceRangeSkipped is called when a source range	is skipped.

       Argument	descriptions:

    +--------------+-------------------------+----------------+------------------+
    |Argument Name | Argument	Value	     | Clang C++ Type |	Description	 |
    |		   | Syntax		     |		      |			 |
    +--------------+-------------------------+----------------+------------------+
    |Range	   | ["(file):(line):(col)", | SourceRange    |	The source range |
    |		   | "(file):(line):(col)"]  |		      |	skipped.	 |
    +--------------+-------------------------+----------------+------------------+

       Example::

	  - Callback: SourceRangeSkipped
	    Range: [":/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-macro.cpp:8:2", ":/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-macro.cpp:9:2"]

   If Callback
       If is called when an #if	is seen.

       Argument	descriptions:

    +---------------+-------------------------+----------------+------------------+
    |Argument Name  | Argument	 Value	      |	Clang C++ Type | Description	  |
    |		    | Syntax		      |		       |		  |
    +---------------+-------------------------+----------------+------------------+
    |Loc	    | "(file):(line):(col)"   |	SourceLocation | The  location of |
    |		    |			      |		       | the directive.	  |
    +---------------+-------------------------+----------------+------------------+
    |ConditionRange | ["(file):(line):(col)", |	SourceRange    | The source range |
    |		    | "(file):(line):(col)"]  |		       | for  the  condi- |
    |		    |			      |		       | tion.		  |
    +---------------+-------------------------+----------------+------------------+
    |ConditionValue | (true|false)	      |	bool	       | The	condition |
    |		    |			      |		       | value.		  |
    +---------------+-------------------------+----------------+------------------+

       Example::

	  - Callback: If
	    Loc: "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-macro.cpp:8:2"
	    ConditionRange: ["D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-macro.cpp:8:4", "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-macro.cpp:9:1"]
	    ConditionValue: false

   Elif	Callback
       Elif is called when an #elif is seen.

       Argument	descriptions:

    +---------------+-------------------------+----------------+------------------+
    |Argument Name  | Argument	 Value	      |	Clang C++ Type | Description	  |
    |		    | Syntax		      |		       |		  |
    +---------------+-------------------------+----------------+------------------+
    |Loc	    | "(file):(line):(col)"   |	SourceLocation | The  location of |
    |		    |			      |		       | the directive.	  |
    +---------------+-------------------------+----------------+------------------+
    |ConditionRange | ["(file):(line):(col)", |	SourceRange    | The source range |
    |		    | "(file):(line):(col)"]  |		       | for  the  condi- |
    |		    |			      |		       | tion.		  |
    +---------------+-------------------------+----------------+------------------+
    |ConditionValue | (true|false)	      |	bool	       | The	condition |
    |		    |			      |		       | value.		  |
    +---------------+-------------------------+----------------+------------------+
    |IfLoc	    | "(file):(line):(col)"   |	SourceLocation | The  location of |
    |		    |			      |		       | the directive.	  |
    +---------------+-------------------------+----------------+------------------+

       Example::

	  - Callback: Elif
	    Loc: "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-macro.cpp:10:2"
	    ConditionRange: ["D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-macro.cpp:10:4", "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-macro.cpp:11:1"]
	    ConditionValue: false
	    IfLoc: "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-macro.cpp:8:2"

   Ifdef Callback
       Ifdef is	called when an #ifdef is seen.

       Argument	descriptions:

    +---------------+-----------------------+------------------+------------------+
    |Argument Name  | Argument	 Value	    | Clang C++	Type   | Description	  |
    |		    | Syntax		    |		       |		  |
    +---------------+-----------------------+------------------+------------------+
    |Loc	    | "(file):(line):(col)" | SourceLocation   | The location  of |
    |		    |			    |		       | the directive.	  |
    +---------------+-----------------------+------------------+------------------+

    |MacroNameTok   | (token)		    | const Token      | The  macro  name |
    |		    |			    |		       | token.		  |
    +---------------+-----------------------+------------------+------------------+
    |MacroDirective | (MD_Define|MD_Unde-   | const   MacroDi- | The   kind    of |
    |		    | fine|MD_Visibility)   | rective	       | macro	directive |
    |		    |			    |		       | from	      the |
    |		    |			    |		       | MacroDirective	  |
    |		    |			    |		       | structure.	  |
    +---------------+-----------------------+------------------+------------------+

       Example::

	  - Callback: Ifdef
	    Loc: "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-conditional.cpp:3:1"
	    MacroNameTok: MACRO
	    MacroDirective: MD_Define

   Ifndef Callback
       Ifndef is called	when an	#ifndef	is seen.

       Argument	descriptions:

    +---------------+-----------------------+------------------+------------------+
    |Argument Name  | Argument	 Value	    | Clang C++	Type   | Description	  |
    |		    | Syntax		    |		       |		  |
    +---------------+-----------------------+------------------+------------------+
    |Loc	    | "(file):(line):(col)" | SourceLocation   | The location  of |
    |		    |			    |		       | the directive.	  |
    +---------------+-----------------------+------------------+------------------+
    |MacroNameTok   | (token)		    | const Token      | The  macro  name |
    |		    |			    |		       | token.		  |
    +---------------+-----------------------+------------------+------------------+
    |MacroDirective | (MD_Define|MD_Unde-   | const   MacroDi- | The   kind    of |
    |		    | fine|MD_Visibility)   | rective	       | macro	directive |
    |		    |			    |		       | from	      the |
    |		    |			    |		       | MacroDirective	  |
    |		    |			    |		       | structure.	  |
    +---------------+-----------------------+------------------+------------------+

       Example::

	  - Callback: Ifndef
	    Loc: "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-conditional.cpp:3:1"
	    MacroNameTok: MACRO
	    MacroDirective: MD_Define

   Else	Callback
       Else is called when an #else is seen.

       Argument	descriptions:

     +--------------+-----------------------+----------------+------------------+
     |Argument Name | Argument	 Value	    | Clang C++	Type | Description	|
     |		    | Syntax		    |		     |			|
     +--------------+-----------------------+----------------+------------------+
     |Loc	    | "(file):(line):(col)" | SourceLocation | The location  of	|
     |		    |			    |		     | the  else direc-	|
     |		    |			    |		     | tive.		|
     +--------------+-----------------------+----------------+------------------+
     |IfLoc	    | "(file):(line):(col)" | SourceLocation | The location  of	|
     |		    |			    |		     | the   if	 direc-	|
     |		    |			    |		     | tive.		|
     +--------------+-----------------------+----------------+------------------+

       Example::

	  - Callback: Else
	    Loc: "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-macro.cpp:10:2"
	    IfLoc: "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-macro.cpp:8:2"

   Endif Callback
       Endif is	called when an #endif is seen.

       Argument	descriptions:

     +--------------+-----------------------+----------------+------------------+
     |Argument Name | Argument	 Value	    | Clang C++	Type | Description	|
     |		    | Syntax		    |		     |			|
     +--------------+-----------------------+----------------+------------------+
     |Loc	    | "(file):(line):(col)" | SourceLocation | The location  of	|
     |		    |			    |		     | the endif direc-	|
     |		    |			    |		     | tive.		|
     +--------------+-----------------------+----------------+------------------+
     |IfLoc	    | "(file):(line):(col)" | SourceLocation | The location  of	|
     |		    |			    |		     | the   if	 direc-	|
     |		    |			    |		     | tive.		|
     +--------------+-----------------------+----------------+------------------+

       Example::

	  - Callback: Endif
	    Loc: "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-macro.cpp:10:2"
	    IfLoc: "D:/Clang/llvm/tools/clang/tools/extra/test/pp-trace/pp-trace-macro.cpp:8:2"

   Building pp-trace
       To build	from source:

       1. Read Getting Started with the	LLVM System and	Clang Tools Documenta-
	  tion	for  information on getting sources for	LLVM, Clang, and Clang
	  Extra	Tools.

       2. Getting Started with the LLVM	System and Building  LLVM  with	 CMake
	  give	directions for how to build. With sources all checked out into
	  the right place the LLVM build will  build  Clang  Extra  Tools  and
	  their	dependencies automatically.

	  o If using CMake, you	can also use the pp-trace target to build just
	    the	pp-trace tool and its dependencies.

CLANG-RENAME
   Contents
       o Clang-Rename

	 o Using Clang-Rename

	 o Vim Integration

	 o Emacs Integration

       See also:

       clang-rename is a C++ refactoring tool. Its purpose is to perform effi-
       cient  renaming	actions	 in  large-scale  projects  such  as  renaming
       classes,	functions, variables, arguments, namespaces etc.

       The tool	is in a	very early development stage, so you  might  encounter
       bugs  and crashes. Submitting reports with information about how	to re-
       produce the issue to the	 LLVM  bugtracker  will	 definitely  help  the
       project.	 If you	have any ideas or suggestions, you might want to put a
       feature request there.

   Using Clang-Rename
       clang-rename is a LibTooling-based tool,	and it's easier	to  work  with
       if you set up a compile command database	for your project (for an exam-
       ple of how to do	this see How To	Setup Tooling For LLVM). You can  also
       specify compilation options on the command line after --:

	  $ clang-rename -offset=42 -new-name=foo test.cpp -- -Imy_project/include -DMY_DEFINES	...

       To get an offset	of a symbol in a file run

	  $ grep -FUbo 'foo' file.cpp

       The  tool  currently supports renaming actions inside a single transla-
       tion unit only. It is planned to	extend	the  tool's  functionality  to
       support multi-TU	renaming actions in the	future.

       clang-rename  also  aims	to be easily integrated	into popular text edi-
       tors, such as Vim and Emacs, and	improve	the workflow of	users.

       Although	a command line interface exists, it is highly  recommended  to
       use the text editor interface instead for better	experience.

       You  can	 also identify one or more symbols to be renamed by giving the
       fully qualified name:

	  $ clang-rename -qualified-name=foo -new-name=bar test.cpp

       Renaming	multiple symbols at once is supported, too. However, clang-re-
       name  doesn't accept both -offset and -qualified-name at	the same time.
       So, you can either specify multiple -offset or -qualified-name.

	  $ clang-rename -offset=42 -new-name=bar1 -offset=150 -new-name=bar2 test.cpp

       or

	  $ clang-rename -qualified-name=foo1 -new-name=bar1 -qualified-name=foo2 -new-name=bar2 test.cpp

       Alternatively, {offset |	qualified-name}	/ new-name pairs  can  be  put
       into a YAML file:

	  ---
	  - Offset:	    42
	    NewName:	    bar1
	  - Offset:	    150
	    NewName:	    bar2
	  ...

       or

	  ---
	  - QualifiedName:  foo1
	    NewName:	    bar1
	  - QualifiedName:  foo2
	    NewName:	    bar2
	  ...

       That way	you can	avoid spelling out all the names as command line argu-
       ments:

	  $ clang-rename -input=test.yaml test.cpp

       clang-rename offers the following options:

	  $ clang-rename --help
	  USAGE: clang-rename [subcommand] [options] <source0> [... <sourceN>]

	  OPTIONS:

	  Generic Options:

	    -help		       - Display available options (-help-hidden for more)
	    -help-list		       - Display list of available options (-help-list-hidden for more)
	    -version		       - Display the version of	this program

	  clang-rename common options:

	    -export-fixes=<filename>   - YAML file to store suggested fixes in.
	    -extra-arg=<string>	       - Additional argument to	append to the compiler command line
	    -extra-arg-before=<string> - Additional argument to	prepend	to the compiler	command	line
	    -force		       - Ignore	nonexistent qualified names.
	    -i			       - Overwrite edited <file>s.
	    -input=<string>	       - YAML file to load oldname-newname pairs from.
	    -new-name=<string>	       - The new name to change	the symbol to.
	    -offset=<uint>	       - Locates the symbol by offset as opposed to <line>:<column>.
	    -p=<string>		       - Build path
	    -pl			       - Print the locations affected by renaming to stderr.
	    -pn			       - Print the found symbol's name prior to	renaming to stderr.
	    -qualified-name=<string>   - The fully qualified name of the symbol.

   Vim Integration
       You can call clang-rename directly from Vim! To set up clang-rename in-
       tegration for Vim see clang/tools/clang-rename/clang-rename.py.

       Please note that	you have to save all buffers, in which the replacement
       will happen before running the tool.

       Once installed, you can point your cursor to symbols you	 want  to  re-
       name, press _leader_cr and type new desired name. The _leader_ key is a
       reference to a specific key defined by the mapleader  variable  and  is
       bound to	backslash by default.

   Emacs Integration
       You can also use	clang-rename while using Emacs!	To set up clang-rename
       integration for Emacs see clang-rename/tool/clang-rename.el.

       Once installed, you can point your cursor to symbols you	 want  to  re-
       name, press M-X,	type clang-rename and new desired name.

       Please note that	you have to save all buffers, in which the replacement
       will happen before running the tool.

CLANGD
   Getting started with	clangd
   Contents
       o Getting started with clangd

	 o Installing clangd

	 o Editor plugins

	 o Project setup

	   o compile_commands.json

	   o compile_flags.txt

	 o Project-wide	Index

       To use clangd, you need to:

       o install clangd,

       o install a plugin for your editor,

       o tell clangd how your project is built.

   Installing clangd
       You need	a recent version of clangd: 7.0	was the	first usable  release,
       and 8.0 is much better.

       After installing, clangd	--version should print clangd version 7.0.0 or
       later.

       Homebrew	can install clangd along with LLVM:

	  $ brew install llvm

       If you don't want to use	Homebrew, you can download the	a  binary  re-
       lease  of  LLVM	from releases.llvm.org.	 Alongside bin/clangd you will
       need at least lib/clang/*/include:

	  $ cp clang+llvm-7.0.0/bin/clangd /usr/local/bin/clangd
	  $ cp -r clang+llvm-7.0.0/lib/clang/ /usr/local/lib/

       Download	and run	the LLVM installer from	releases.llvm.org.

       The clang-tools package usually contains	an old version of clangd.

       Try to install the latest release (8.0):

	  $ sudo apt-get install clang-tools-8

       If that is not found, at	least clang-tools-7 should be available.

       The clangd executable will be installed as /usr/bin/clangd-8.  Make  it
       the default clangd:

	  $ sudo update-alternatives --install /usr/bin/clangd clangd /usr/bin/clangd-8	100

       Most  distributions  include clangd in a	clang-tools package, or	in the
       full llvm distribution.

       For some	platforms, binaries are	also avaliable at releases.llvm.org.

   Editor plugins
       Language	Server plugins are available for many editors.	In  principle,
       clangd  should work with	any of them, though the	feature	set and	UI may
       vary.

       Here are	some plugins we	know work well with clangd.

       YouCompleteMe supports clangd.  However,	clangd support is  not	turned
       on  by  default,	 so  you  must	install	 YouCompleteMe with install.py
       --clangd-completer.

       We recommend changing a couple of YCM's	default	 settings.  In	.vimrc
       add:

	  " Let	clangd fully control code completion
	  let g:ycm_clangd_uses_ycmd_caching = 0
	  " Use	installed clangd, not YCM-bundled clangd which doesn't get updates.
	  let g:ycm_clangd_binary_path = exepath("clangd")

       You  should  see	 errors	 highlighted and code completions as you type.
       [image: Code completion in YouCompleteMe] [image]

       YouCompleteMe supports many of clangd's features:

       o code completion,

       o diagnostics and fixes (:YcmCompleter FixIt),

       o find declarations, references,	and  definitions  (:YcmCompleter  GoTo
	 etc),

       o rename	symbol (:YcmCompleter RefactorRename).

       Under the hood

       o Debug	logs: run :YcmDebugInfo	to see clangd status, and :YcmToggleL-
	 ogs to	view clangd's debug logs.

       o Command-line flags: Set g:ycm_clangd_args in .vimrc, e.g.:

	    let	g:ycm_clangd_args = ['-log=verbose', '-pretty']

       o Alternate clangd binary: set g:ycm_clangd_binary_path in .vimrc.

       LanguageClient-neovim has instructions for using	 clangd,  and  may  be
       easier to install than YouCompleteMe.

       eglot can be configured to work with clangd.

       Install eglot with M-x package-install RET eglot	RET.

       Add the following to ~/.emacs to	enable clangd:

	  (require 'eglot)
	  (add-to-list 'eglot-server-programs '((c++-mode c-mode) "clangd"))
	  (add-hook 'c-mode-hook 'eglot-ensure)
	  (add-hook 'c++-mode-hook 'eglot-ensure)

       After  restarting  you  should see diagnostics for errors in your code,
       and M-x completion-at-point should work.	 [image: Diagnostics in	Emacs]
       [image]

       eglot supports many of clangd's features, with caveats:

       o code completion, though the interaction is quite poor (even with com-
	 pany-mode, see	below),

       o diagnostics and fixes,

       o find definitions and references (M-x xref-find-definitions etc),

       o hover and highlights,

       o code actions (M-x eglot-code-actions).

       company-mode

       eglot does have basic integration with company-mode, which  provides  a
       more fluent completion UI.

       You can install it with M-x package-install RET company RET, and	enable
       it with M-x company-mode.

       company-clang is	enabled	by default, and	will  interfere	 with  clangd.
       Disable it in M-x customize-variable RET	company-backends RET.

       Completion still	has some major limitations:

       o completions are alphabetically	sorted,	not ranked.

       o only pure-prefix completions are shown	- no fuzzy matches.

       o completion triggering seems to	be a bit hit-and-miss.
       [image: Completion in company-mode] [image]

       Under the hood

       o Debug logs: available in the EGLOT stderr buffer.

       o Command-line  flags  and alternate binary: instead of adding "clangd"
	 to eglot-server-programs, add ("/path/to/clangd" "-log=verbose") etc.

       The official extension is  vscode-clangd	 and  can  be  installed  from
       within VSCode.

       Choose  View  -->  Extensions, then search for "clangd".	(Make sure the
       Microsoft C/C++ extension is not	installed).

       After restarting, you should see	red underlines underneath errors,  and
       you  should  get	 rich code completions including e.g. function parame-
       ters.  [image: Code completion in VSCode] [image]

       vscode-clangd has excellent support for all clangd features, including:

       o code completion

       o diagnostics and fixes

       o find declarations, references,	and definitions

       o find symbol in	file (Ctrl-P @foo) or workspace	(Ctrl-P	#foo)

       o hover and highlights

       o code actions

       Under the hood

       o Debug logs: when clangd is running, you should	 see  "Clang  Language
	 Server" in the	dropdown of the	Output panel (View -> Output).

       o Command-line flags: these can be passed in the	clangd.arguments array
	 in your settings.json.	(File -> Preferences ->	Settings).

       o Alternate clangd binary: set the clangd.path string in	settings.json.

       tomv564/LSP works with clangd out of the	box.

       Select Tools -->	Install	Package	Control	(if you	haven't	 installed  it
       yet).

       Press  Ctrl-Shift-P and select Package Control: Install Package.	Select
       LSP.

       Press Ctrl-Shift-P and select LSP:  Enable  Language  Server  Globally.
       Select clangd.

       Open a C++ file,	and you	should see diagnostics and completion: [image:
       Code completion in Sublime Text]	[image]

       The LSP package has excellent support for all most clangd features, in-
       cluding:

       o code completion (a bit	noisy due to how snippets are presented)

       o diagnostics and fixes

       o find definition and references

       o hover and highlights

       o code actions

       Under the hood

       Settings	can be tweaked under Preferences --> Package Settings --> LSP.

       o Debug logs: add "log_stderr": true

       o Command-line flags and	alternate clangd binary: inside	the "clients":
	 {"clangd": { ... }  }	section,  add  "command":  ["/path/to/clangd",
	 "-log=verbose"] etc.

       There is	a directory of LSP clients at langserver.org.

       A  generic  client  should be configured	to run the command clangd, and
       communicate via the language server protocol on standard	input/output.

       If you don't have strong	feelings about an editor, we suggest  you  try
       out  VSCode,  it	 has excellent language	server support and most	faith-
       fully demonstrates what clangd can do.

   Project setup
       To understand source code in your project, clangd  needs	 to  know  the
       build flags.  (This is just a fact of life in C++, source files are not
       self-contained.)

       By default, clangd will assume that  source  code  is  built  as	 clang
       some_file.cc,  and  you'll  probably  get spurious errors about missing
       #included files,	etc.  There are	a couple of ways to fix	this.

   compile_commands.json
       compile_commands.json file provides compile  commands  for  all	source
       files in	the project.  This file	is usually generated by	the build sys-
       tem, or tools integrated	with the build system.	Clangd will  look  for
       this file in the	parent directories of the files	you edit.

       If  your	 project  builds  with	CMake,	it  can	 generate compile_com-
       mands.json.  You	should enable it with:

	  $ cmake -DCMAKE_EXPORT_COMPILE_COMMANDS=1

       compile_commands.json will be written to	 your  build  directory.   You
       should symlink it (or copy it) to the root of your source tree, if they
       are different.

	  $ ln -s ~/myproject-build/compile_commands.json ~/myproject/

       Bear is a tool that generates a compile_commands.json file by recording
       a complete build.

       For  a  make-based build, you can run make clean; bear make to generate
       the file	(and run a clean build!)

       Other tools can also generate this file.	See the	 compile_commands.json
       specification.

   compile_flags.txt
       If  all	files in a project use the same	build flags, you can put those
       flags, one flag per line, in compile_flags.txt in your source root.

       Clangd will assume the compile command is clang $FLAGS some_file.cc.

       Creating	this file by hand is a	reasonable  place  to  start  if  your
       project is quite	simple.

   Project-wide	Index
       By  default clangd only has a view on symbols coming from files you are
       currently editing. You can extend this view to whole project by provid-
       ing a project-wide index	to clangd.  There are two ways to do this.

       o Pass  an  experimental	-background-index command line argument.  With
	 this  feature	enabled,  clangd  incrementally	 builds	 an  index  of
	 projects  that	 you  work  on and uses	the just-built index automati-
	 cally.

       o Generate an index file	using clangd-indexer Then you can pass	gener-
	 ated  index  file  to	clangd	using -index-file=/path/to/index_file.
	 Note that clangd-indexer isn't	included alongside clangd in  the  De-
	 bian  clang-tools  package.  You  will	 likely	 have to build it from
	 source	to use this option.

   Features
   Contents
       o Features

	 o Errors and warnings

	   o Fixes in errors and warnings

	   o clang-tidy	checks

	 o Code	completion

	   o Insertion of namespace qualifiers and includes

	   o Signature help

	 o Cross-references

	   o Find definition/declaration

	   o Find references

	 o Navigation

	 o Formatting

	 o Complete list of features

       Here is what clangd can do for you.  Screenshots	below show VSCode; the
       available features and UI depend	on the editor.

   Errors and warnings
       clangd  runs the	clang compiler on your code as you type, and shows er-
       rors and	warnings in-place.  Some errors	 are  suppressed:  diagnostics
       that  require  expanding	 templates in headers are disabled for perfor-
       mance reasons.

       [image: Demonstration of	errors]	[image]

   Fixes in errors and warnings
       The compiler can	suggest	fixes for many common problems	automatically,
       and clangd can update the code for you.

       [image: Applying	a fix suggested	by the compiler] [image]

       (New  in	 v9)  If a missing symbol was seen in a	file you've edited re-
       cently, clangd will suggest inserting it.

   clang-tidy checks
       (New in v9) clangd embeds clang-tidy which provides extra  hints	 about
       code problems: bug-prone	patterns, performance traps, and style issues.

       [image: Applying	a fix suggested	by the compiler] [image]

       clangd  respects	 your  project's  .clang-tidy  file which controls the
       checks to run. Not all checks work within clangd.  You  must  pass  the
       -clang-tidy flag	to enable this feature.

   Code	completion
       You'll  see  suggestions	 as you	type based on what methods, variables,
       etc are available in this context.

       [image: Code completion demonstration] [image]

       Abbreviating words may help you find the	right result  faster.  If  you
       type  in	 camelCase  but	the function you're looking for	is snake_case,
       that's OK.

   Insertion of	namespace qualifiers and includes
       (New in v8) clangd will sometimes suggest results from other files  and
       namespaces.  In	this case the correct qualifier	and #include directive
       will be inserted.

       [image: Code completion inserts namespace qualifiers] [image]

   Signature help
       Some editors will show you the parameters of the	function you're	 call-
       ing, as you fill	them in.

       [image: Demonstration of	the signature help feature] [image]

   Cross-references
       The following features let you navigate your codebase.

       If  there  is  no  project-wide index, cross-references work across the
       files you have opened.

       (New in v9) clangd will also automatically index	your whole project.

   Find	definition/declaration
       Jump to the definition or declaration of	a symbol under the cursor.

       [image: Demonstration of	the "Go	to definition" feature]	[image]

       (New in v9) Some	editors	only expose "find definition"; use "find defi-
       nition" on the definition to jump to the	declaration.

       "Find definition" also works on #include	lines, to jump to the included
       file.

   Find	references
       Show all	references to a	symbol under the cursor.

       [image: Demonstration of	the "Find all references" feature] [image]

       Some editors will automatically highlight local references to  the  se-
       lected symbol as	you move around	a file.

   Navigation
       clangd  informs	the  editor of the code	structure in the current file.
       Some editors use	this to	present	an outline view:

       [image: Outline of a file] [image]

       In VSCode, the outline is also  presented  as  breadcrumbs  that	 allow
       jumping	to  a  symbol  within the current file.	 Searching for symbols
       within the scope	of the whole project is	also possible.

       [image: Navigation with breadcrumbs] [image]

   Formatting
       clangd embeds clang-format, which can reformat your code: fixing	inden-
       tation, breaking	lines, and reflowing comments.

       [image: Formatting selected code] [image]

       clangd  respects	 your  project's  .clang-format	 file  which  controls
       styling options.

       Format-as-you-type is experimental and doesn't work well	yet.

   Complete list of features
       Here is a list of features that could be	useful for  editors,  together
       with the	implementation status in clangd, and specification in the Lan-
       guage Server Protocol.

       It is not clear whether or not some of  the  features  mentioned	 below
       should  be a part of the	Language Server	Protocol; those	features might
       be eventually developed outside clangd or become	clangd	extensions  to
       LSP.

			+--------------------+-----+--------+
			|C/C++	Editor	fea- | LSP | Clangd |
			|ture		     |	   |	    |
			+--------------------+-----+--------+
			|Formatting	     | Yes | Yes    |
			+--------------------+-----+--------+
			|Completion	     | Yes | Yes    |
			+--------------------+-----+--------+
			|Diagnostics	     | Yes | Yes    |
			+--------------------+-----+--------+
			|Fix-its	     | Yes | Yes    |
			+--------------------+-----+--------+
			|Go to Definition    | Yes | Yes    |
			+--------------------+-----+--------+
			|Signature Help	     | Yes | Yes    |
			+--------------------+-----+--------+
			|Document Highlights | Yes | Yes    |
			+--------------------+-----+--------+
			|Rename		     | Yes | Yes    |
			+--------------------+-----+--------+
			|Source	hover	     | Yes | Yes    |
			+--------------------+-----+--------+
			|Find References     | Yes | Yes    |
			+--------------------+-----+--------+
			|Document Symbols    | Yes | Yes    |
			+--------------------+-----+--------+
			|Workspace Symbols   | Yes | Yes    |
			+--------------------+-----+--------+
			|Code Lens	     | Yes | No	    |
			+--------------------+-----+--------+
			|Code folding	     | Yes | No	    |
			+--------------------+-----+--------+
			|Extract Local Vari- | Yes | No	    |
			|able		     |	   |	    |
			+--------------------+-----+--------+
			|Extract       Func- | Yes | No	    |
			|tion/Method	     |	   |	    |
			+--------------------+-----+--------+
			|Quick Assist	     | Yes | No	    |
			+--------------------+-----+--------+
			|Hide Method	     | Yes | No	    |
			+--------------------+-----+--------+
			|Implement Method    | Yes | No	    |
			+--------------------+-----+--------+
			|Gen.	Getters/Set- | Yes | No	    |
			|ters		     |	   |	    |
			+--------------------+-----+--------+
			|Syntax	and Semantic | No  | No	    |
			|Coloring	     |	   |	    |
			+--------------------+-----+--------+
			|Call hierarchy	     | No  | No	    |
			+--------------------+-----+--------+
			|Type hierarchy	     | No  | Yes    |
			+--------------------+-----+--------+
			|Organize Includes   | No  | No	    |
			+--------------------+-----+--------+

   What	is clangd?
       clangd understands your C++ code	and adds smart features	to  your  edi-
       tor: code completion, compile errors, go-to-definition and more.

       clangd  is a language server that implements the	Language Server	Proto-
       col; it can work	with many editors through  a  plugin.	Here's	Visual
       Studio Code with	the clangd plugin, demonstrating code completion: [im-
       age: Code completion in VSCode] [image]

       clangd is based on the Clang C++	compiler, and  is  part	 of  the  LLVM
       project.

DEVELOPER DOCUMENTATION	FOR CLANGD
   Protocol extensions
   Contents
       o Protocol extensions

	 o Switch between the implementation file and the header

	 o File	status

	 o Compilation commands

	 o Force diagnostics generation

	 o Diagnostic categories

	 o Inline fixes	for diagnostics

	 o Symbol info request

       clangd  supports	 some  features	 that are not in the official Language
       Server Protocol specification.

       We cautious about adding	extensions. The	most important	considerations
       are:

       o Editor	support: How many users	will the feature be available to?

       o Standardization: Is the feature stable? Is it likely to be adopted by
	 more editors over time?

       o Utility: Does the feature provide a lot of value?

       o Complexity: Is	this hard to implement in clangd, or constrain	future
	 work?	Is the protocol	complicated?

       These  extensions  may  evolve or disappear over	time. If you use them,
       try to recover gracefully if the	structures aren't what's expected.

   Switch between the implementation file and the header
       This extension is supported in clangd 6 and newer.

       Switching between the implementation file and the header	is  an	impor-
       tant  feature for C++.  A language server that understands C++ can do a
       better job than the editor.

       New client->server request: textDocument/switchSourceHeader.

       Lets editors switch between the main source  file  (*.cpp)  and	header
       (*.h).

       Parameter: TextDocumentIdentifier: an open file.

       Result:	string:	 the URI of the	corresponding header (if a source file
       was provided) or	source file (if	a header was provided).

       If the corresponding file can't be determined, "" is returned.

   File	status
       This extension is supported in clangd 8 and newer.

       It is important to provide feedback to the user when the	UI is not  re-
       sponsive.

       This extension provides information about activity on clangd's per-file
       worker thread.  This information	can be displayed to users to let  them
       know  that the language server is busy with something.  For example, in
       clangd, building	the AST	blocks many other operations.

       New server->client notification:	textDocument/clangd.fileStatus

       Sent when the current activity for a file  changes.  Replaces  previous
       activity	for that file.

       Parameter: FileStatus object with properties:

       o uri : string: the document whose status is being updated.

       o state : string: human-readable	information about current activity.

       New  initialization  option:  initializationOptions.clangdFileStatus  :
       bool

       Enables receiving textDocument/clangd.fileStatus	notifications.

   Compilation commands
       This extension is supported in clangd 8 and newer.

       clangd relies on	knowing	accurate compilation options to	correctly  in-
       terpret	a  file.  Typically  they are found in a compile_commands.json
       file in a directory that	contains the file, or an  ancestor  directory.
       The  following extensions allow editors to supply the commands over LSP
       instead.

       New    initialization	option:	    initializationOptions.compilation-
       DatabasePath : string

       Specifies the directory containing the compilation database (e.g., com-
       pile_commands.json). This path will be used for all files,  instead  of
       searching their ancestor	directories.

       New   initialization   option:	initializationOptions.fallbackFlags  :
       string[]

       Controls	the flags used when no specific	compile	command	is found.  The
       compile	command	 will  be  approximately clang $FILE $fallbackFlags in
       this case.

       New  configuration   setting:   settings.compilationDatabaseChanges   :
       {string:	CompileCommand}

       Provides	 compile  commands  for	 files.	 This  can also	be provided on
       startup as initializationOptions.compilationDatabaseChanges.

       Keys are	file paths (Not	URIs!)

       Values are {workingDirectory: string, compilationCommand: string[]}.

   Force diagnostics generation
       This extension is supported in clangd 7 and newer.

       Clangd does not regenerate diagnostics for  every  version  of  a  file
       (e.g.,  after  every keystroke),	as that	would be too slow. Its heuris-
       tics ensure:

       o diagnostics do	not get	too stale,

       o if you	stop editing, diagnostics will catch up.

       This extension allows editors to	force diagnostics to be	 generated  or
       not generated at	a particular revision.

       New property of textDocument/didChange request: wantDiagnostics : bool

       o if true, diagnostics will be produced for exactly this	version.

       o if  false, diagnostics	will not be produced for this version, even if
	 there are no further edits.

       o if unset, diagnostics will be produced	for this version or some  sub-
	 sequent one in	a bounded amount of time.

   Diagnostic categories
       This extension is supported in clangd 8 and newer.

       Clang compiler groups diagnostics into categories (e.g.,	"Inline	Assem-
       bly Issue").  Clangd can	emit these categories for interested editors.

       New property of Diagnostic object: category : string:

       A human-readable	name for a group of related diagnostics.   Diagnostics
       with the	same code will always have the same category.

       New client capability: textDocument.publishDiagnostics.categorySupport:

       Requests	that clangd send Diagnostic.category.

   Inline fixes	for diagnostics
       This extension is supported in clangd 8 and newer.

       LSP  specifies  that code actions for diagnostics (fixes) are retrieved
       asynchronously using textDocument/codeAction.  clangd  always  computes
       fixes eagerly.  Providing them alongside	diagnostics can	improve	the UX
       in editors.

       New property of Diagnostic object: codeActions :	CodeAction[]:

       All the code actions that address this diagnostic.

       New client  capability:	textDocument.publishDiagnostics.codeActionsIn-
       line : bool

       Requests	clangd to send Diagnostic.codeActions.

   Symbol info request
       This extension is supported in clangd 8 and newer.

       New client->server request: textDocument/symbolInfo:

       This  request  attempts to resolve the symbol under the cursor, without
       retrieving further information (like definition location, which may re-
       quire consulting	an index).  This request was added to support integra-
       tion with indexes outside clangd.

       Parameter: TextDocumentPositionParams

       Response: SymbolDetails,	an object with properties:

       o name :	string the unqualified name of the symbol

       o containerName : string	the enclosing namespace,  class	 etc  (without
	 trailing ::)

       o usr  :	string:	the clang-specific "unified symbol resolution" identi-
	 fier

       o id : string?: the clangd-specific opaque symbol ID

   Compiling clangd
       To build	 clangd	 from  source,	please	follow	the  instructions  for
       building	 Clang and include LLVM, Clang,	and the	"extra Clang tools" in
       your build.

   Contributing	to clangd
       A good place for	interested contributors	is the Clangd developer	 mail-
       ing list. For discussions with the broader community on topics not only
       related to Clangd, use Clang developer mailing list.   If  you're  also
       interested  in  contributing patches to clangd, take a look at the LLVM
       Developer Policy	and Code Reviews page. Contributions of	 new  features
       to  the	Language  Server Protocol itself would also be very useful, so
       that clangd can eventually implement them in a conforming way.

CLANG-DOC
   Contents
       o Clang-Doc

	 o Use

       clang-doc is a tool for generating C and	C++ documenation  from	source
       code and	comments.

       The  tool  is in	a very early development stage,	so you might encounter
       bugs and	crashes. Submitting reports with information about how to  re-
       produce	the  issue  to	the  LLVM  bugtracker will definitely help the
       project.	If you have any	ideas or suggestions, please to	put a  feature
       request there.

   Use
       clang-doc is a LibTooling-based tool, and so requires a compile command
       database	for your project (for an example of how	to do this see How  To
       Setup Tooling For LLVM).

       The  tool  can be used on a single file or multiple files as defined in
       the compile commands database:

	  $ clang-doc /path/to/file.cpp	-p /path/to/compile/commands

       This generates an intermediate representation of	the  declarations  and
       their  associated  information in the specified TUs, serialized to LLVM
       bitcode.

       As currently implemented, the tool is only able to parse	TUs  that  can
       be stored in-memory. Future additions will extend the current framework
       to use map-reduce frameworks to allow for use with large	codebases.

       clang-doc offers	the following options:

		$ clang-doc --help
	  USAGE: clang-doc [options] <source0> [... <sourceN>]

	  OPTIONS:

	  Generic Options:

	    -help		       - Display available options (-help-hidden for more)
	    -help-list		       - Display list of available options (-help-list-hidden for more)
	    -version		       - Display the version of	this program

	  clang-doc options:

	    -doxygen		       - Use only doxygen-style	comments to generate docs.
	    -dump		       - Dump intermediate results to bitcode file.
	    -extra-arg=<string>	       - Additional argument to	append to the compiler command line
	    -extra-arg-before=<string> - Additional argument to	prepend	to the compiler	command	line
	    -omit-filenames	       - Omit filenames	in output.
	    -output=<string>	       - Directory for outputting generated files.
	    -p=<string>		       - Build path

       The Doxygen documentation describes the internal	software that makes up
       the  tools  of  clang-tools-extra, not the external use of these	tools.
       The Doxygen documentation contains no instructions about	how to use the
       tools, only the APIs that make up the software. For usage instructions,
       please see the user's guide or reference	manual for each	tool.

       o Doxygen documentation

       NOTE:
	  This documentation is	generated directly from	the source  code  with
	  doxygen.   Since the tools of	clang-tools-extra are constantly under
	  active development, what you're about	to read	is out of date!

       o genindex

       o search

AUTHOR
       The Clang Team

COPYRIGHT
       2007-2020, The Clang Team

9				 Aug 27, 2020		    EXTRACLANGTOOLS(1)

NAME | EXTRA CLANG TOOLS 9.0.0 RELEASE NOTES | CLANG-TIDY | CLANG-INCLUDE-FIXER | MODULARIZE USER'S MANUAL | PP-TRACE USER'S MANUAL | CLANG-RENAME | CLANGD | DEVELOPER DOCUMENTATION FOR CLANGD | CLANG-DOC | AUTHOR | COPYRIGHT

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