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LINT(1)			  BSD General Commands Manual		       LINT(1)

     lint -- a C program verifier

     lint [-abceFgHhPprVvwxz] [-i | -nu] [-S | -s | -t]	[-B directory]
	  [-D name[=def]] [-d directory] [-I directory]	[-L directory] [-MD]
	  [-l library] [-o outputfile] [-U name] [-X id[,id ...]] file ...
     lint [-abceFgHhprVvwz] [-S	| -s | -t] -C library [-B directory]
	  [-D name[=def]] [-d directory] [-I directory]	[-MD] [-U name]
	  [-X id[,id ...]] file	...

     lint attempts to detect features of the named C program files that	are
     likely to be bugs,	to be non-portable, or to be wasteful.	It also	per-
     forms stricter type checking than does the	C compiler.  The list of er-
     rors lint produces	are enumerated in lint(7).

     lint runs the C preprocessor as its first phase, with the following pre-
     processor symbols defined to allow	certain	questionable code to be	al-
     tered or skipped: __LINT__, lint, __lint, __lint__.  These	symbols	should
     therefore be thought of as	reserved words for all code that is to be
     checked by	lint.

     Among the possible	problems that are currently noted are unreachable
     statements, loops not entered at the top, variables declared and not
     used, and logical expressions with	constant values.  Function calls are
     checked for inconsistencies, such as calls	to functions that return val-
     ues in some places	and not	in others, functions called with varying num-
     bers of arguments,	function calls that pass arguments of a	type other
     than the type the function	expects	to receive, functions whose values are
     not used, and calls to functions not returning values that	use the	non-
     existent return value of the function.

     Filename arguments	ending with .c are taken to be C source	files.	File-
     name arguments with names ending with .ln are taken to be the result of
     an	earlier	invocation of lint, with either	the -i,	-o or -C option	in ef-
     fect.  The	.ln files are analogous	to the .o (object) files produced by
     cc(1) from	.c files.  lint	also accepts special libraries specified with
     the -l option, which contain definitions of library routines and vari-

     lint takes	all the	.c, .ln, and llib-llibrary.ln (lint library) files and
     processes them in command-line order.  By default,	lint appends the stan-
     dard C lint library (llib-lc.ln) to the end of the	list of	files.	When
     the -i option is used, the	.ln files are ignored.	Also, when the -o or
     -i	options	are used, the llib-llibrary.ln files are ignored.  When	the -i
     option is omitted the second pass of lint checks this list	of files for
     mutual compatibility.  At this point, if a	complaint stems	not from a
     given source file,	but from one of	its included files, the	source file-
     name will be printed followed by a	question mark.

     The special input file name "-" causes lint to take input from standard
     input (until end of file) and process it as if it were a .c file.	If the
     -i	flag is	given and "-" is named as one of the input files, the -o flag
     must also be specified to provide an output file name.


     -a		       Report assignments of long values to variables that are
		       not long.

     -aa	       Additional to -a, report	all assignments	of integer
		       values to other integer values which cause implicit
		       narrowing conversion.

     -Bpath	       Path to use when	looking	for the	lint1 and lint2	bina-
		       ries.  Defaults to /usr/libexec.

     -b		       Report break statements that cannot be reached.	This
		       is not the default because, unfortunately, most lex(1)
		       and many	yacc(1)	outputs	produce	many such complaints.

     -Clibrary	       Create a	lint library with the name llib-llibrary.ln.
		       This library is built from all .c and .ln input files.
		       After all global	definitions of functions and variables
		       in these	files are written to the newly created li-
		       brary, lint checks all input files, including libraries
		       specified with the -l option, for mutual	compatibility.

     -c		       Complain	about casts which have questionable portabil-

     -Dname[=def]      Define name for cpp(1), as if by	a #define directive.
		       If no definition	is given, name is defined as 1.

     -ddirectory       Use directory instead of	/usr/include as	the default
		       place to	find include files.

     -e		       Complain	about unusual operations on enum-Types and
		       combinations of enum- and integer-Types.

     -F		       Print pathnames of files.  lint normally	prints the
		       filename	without	the path.

     -g		       Don't print warnings for	some extensions	of gcc(1) to
		       the C language.	Currently these	are nonconstant	ini-
		       tializers in automatic aggregate	initializations,
		       arithmetic on pointer to	void, trailing commas in enum
		       declarations, C++ -style	"//" comments, zero sized
		       structures, subscripting	of non-lvalue arrays, proto-
		       types overriding	old style function declarations	and
		       long long integer types.	 The -g	flag also turns	on the
		       keywords	asm and	inline (alternative keywords with
		       leading underscores for both asm	and inline are always

     -H		       If a complaint stems from an included file lint prints
		       the name	of the included	file instead of	the source
		       file name followed by a question	mark.

     -h		       Apply a number of heuristic tests to attempt to intuit
		       bugs, improve style, and	reduce waste.

     -Idirectory       Add directory to	the list of directories	in which to
		       search for include files.

     -i		       Produce a .ln file for every .c file on the command
		       line.  These .ln	files are the product of lint's	first
		       pass only, and are not checked for compatibility	be-
		       tween functions.

     -Ldirectory       Search for lint libraries in directory and
		       directory/lint before searching the standard place.

     -llibrary	       Include the lint	library	llib-llibrary.ln.

     -MD	       Pass -MD	to cpp(1) causing cpp to create	files contain-
		       ing dependency information for each source file.

     -n		       Do not check compatibility against the standard li-

     -ooutputfile      Name the	output file outputfile.	 The output file pro-
		       duced is	the input that is given	to lint's second pass.
		       The -o option simply saves this file in the named out-
		       put file.  If the -i option is also used	the files are
		       not checked for compatibility.  To produce a
		       llib-llibrary.ln	without	extraneous messages, use of
		       the -u option is	suggested.  The	-v option is useful if
		       the source file(s) for the lint library are just	exter-
		       nal interfaces.

     -P		       Enable more portability warnings: Enum comparisons,
		       sign extension issues when assigning to wider integer
		       types, overflow warnings	when assigning to wider	types.

     -p		       Attempt to check	portability of code to other dialects
		       of C.

     -r		       In case of redeclarations report	the position of	the
		       previous	declaration.

     -S		       C9X mode.  Currently not	fully implemented.

     -s		       Strict ANSI C mode.  Issue warnings and errors required
		       by ANSI C.  Also	do not produce warnings	for constructs
		       which behave differently	in traditional C and ANSI C.
		       With the	-s flag, __STRICT_ANSI__ is a predefined pre-
		       processor macro.

     -t		       Traditional C mode.  __STDC__ is	not predefined in this
		       mode.  Warnings are printed for constructs not allowed
		       in traditional C.  Warnings for constructs which	behave
		       differently in traditional C and	ANSI C are suppressed.
		       Preprocessor macros describing the machine type (e.g.
		       sun3) and machine architecture (e.g.  m68k) are defined
		       without leading and trailing underscores.  The keywords
		       const, volatile and signed are not available in tradi-
		       tional C	mode (although the alternative keywords	with
		       leading underscores still are).

     -Uname	       Remove any initial definition of	name for the pre-

     -u		       Do not complain about functions and external variables
		       used and	not defined, or	defined	and not	used (this is
		       suitable	for running lint on a subset of	files compris-
		       ing part	of a larger program).

     -V		       Print the command lines constructed by the controller
		       program to run the C preprocessor and lint's first and
		       second pass.

     -v		       Suppress	complaints about unused	arguments in func-

     -w		       Treat warnings as errors.

     -X	id[,id ...]    Suppress	error messages identified by the list of ids.
		       A list of messages and ids can be found in lint(7).

     -x		       Report variables	referred to by extern declarations,
		       but never used.

     -z		       Do not complain about structures	that are never defined
		       (for example, using a structure pointer without knowing
		       its contents).

     Input Grammar

     lint's first pass reads standard C	source files.  lint recognizes the
     following C comments as commands.

     /*	ARGSUSEDn */
		 Makes lint check only the first n arguments for usage;	a
		 missing n is taken to be 0 (this option acts like the -v op-
		 tion for the next function).

		 Suppress error	messages about illegal bitfield	types if the
		 type is an integer type, and suppress non-portable bitfield
		 type warnings.

		 Suppress complaints about constant operands for the next ex-

     /*	FALLTHRU */ or /* FALLTHROUGH */
		 Suppress complaints about fall	through	to a case or default
		 labeled statement.  This directive should be placed immedi-
		 ately preceding the label.

     /*	LINTLIBRARY */
		 At the	beginning of a file, mark all functions	and variables
		 defined in this file as used.	Also shut off complaints about
		 unused	function arguments.

     /*	LINTED [comment] */ or /* NOSTRICT [comment] */
		 Suppresses any	intra-file warning except those	dealing	with
		 unused	variables or functions.	 This directive	should be
		 placed	on the line immediately	preceding where	the lint warn-
		 ing occurred.

     /*	LONGLONG */
		 Suppress complaints about use of long long integer types.

     /*	NOTREACHED */
		 At appropriate	points,	inhibit	complaints about unreachable
		 code.	(This comment is typically placed just after calls to
		 functions like	exit(3)).

     /*	PRINTFLIKEn */
		 Makes lint check the first (n-1) arguments as usual.  The
		 n-th argument is interpreted as a printf format string	that
		 is used to check the remaining	arguments.

     /*	PROTOLIBn */
		 Causes	lint to	treat function declaration prototypes as func-
		 tion definitions if n is non-zero.  This directive can	only
		 be used in conjunction	with the /* LINTLIBRARY	*/ directive.
		 If n is zero, function	prototypes will	be treated normally.

     /*	SCANFLIKEn */
		 Makes lint check the first (n-1) arguments as usual.  The
		 n-th argument is interpreted as a scanf format	string that is
		 used to check the remaining arguments.

     /*	VARARGSn */
		 Suppress the usual checking for variable numbers of arguments
		 in the	following function declaration.	 The data types	of the
		 first n arguments are checked;	a missing n is taken to	be 0.

     The behavior of the -i and	the -o options allows for incremental use of
     lint on a set of C	source files.  Generally, one invokes lint once	for
     each source file with the -i option.  Each	of these invocations produces
     a .ln file	that corresponds to the	.c file, and prints all	messages that
     are about just that source	file.  After all the source files have been
     separately	run through lint, it is	invoked	once more (without the -i op-
     tion), listing all	the .ln	files with the needed -llibrary	options.  This
     will print	all the	inter-file inconsistencies.  This scheme works well
     with make(1); it allows make(1) to	be used	to lint	only the source	files
     that have been modified since the last time the set of source files were

     LIBDIR	 The directory where the lint libraries	specified by the
		 -llibrary option must exist.  If this environment variable is
		 undefined, then the default path /usr/libdata/lint will be
		 used to search	for the	libraries.

     TMPDIR	 Usually the path for temporary	files can be redefined by set-
		 ting this environment variable.

     CC		 Location of the C compiler program.  Defaults to /usr/bin/cc.

     /usr/libexec/lint[12]	   programs
     /usr/libdata/lint/llib-l*.ln  various prebuilt lint libraries
     /tmp/lint*			   temporaries

     cc(1), cpp(1), make(1), lint(7)

     Jochen Pohl

     The routines exit(3), longjmp(3) and other	functions that do not return
     are not understood; this causes various incorrect diagnostics.

     Static functions which are	used only before their first extern declara-
     tion are reported as unused.

     Libraries created by the -o option	will, when used	in later lint runs,
     cause certain errors that were reported when the libraries	were created
     to	be reported again, and cause line numbers and file names from the
     original source used to create those libraries to be reported in error
     messages.	For these reasons, it is recommended to	use the	-C option to
     create lint libraries.

BSD				August 2, 2008				   BSD


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