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LD(1)			     GNU Development Tools			 LD(1)

NAME
       ld - Using LD, the GNU linker

SYNOPSIS
       ld [options] objfile ...

DESCRIPTION
       ld  combines a number of	object and archive files, relocates their data
       and ties	up symbol references. Usually the last	step  in  compiling  a
       program is to run ld.

       ld  accepts  Linker  Command  Language  files  written in a superset of
       AT&T's Link Editor Command Language syntax, to provide explicit and to-
       tal control over	the linking process.

       This  man page does not describe	the command language; see the ld entry
       in "info", or the manual	ld: the	GNU linker, for	full  details  on  the
       command language	and on other aspects of	the GNU	linker.

       This version of ld uses the general purpose BFD libraries to operate on
       object files. This allows ld to read, combine, and write	 object	 files
       in  many	 different  formats---for example, COFF	or "a.out".  Different
       formats may be linked together to produce any available kind of	object
       file.

       Aside  from  its	flexibility, the GNU linker is more helpful than other
       linkers in providing diagnostic information.  Many linkers abandon exe-
       cution  immediately  upon  encountering an error; whenever possible, ld
       continues executing, allowing you to identify other errors (or, in some
       cases, to get an	output file in spite of	the error).

       The GNU linker ld is meant to cover a broad range of situations,	and to
       be as compatible	as possible with other linkers.	 As a result, you have
       many choices to control its behavior.

OPTIONS
       The  linker  supports a plethora	of command-line	options, but in	actual
       practice	few of them are	used in	any particular context.	 For instance,
       a  frequent  use	of ld is to link standard Unix object files on a stan-
       dard, supported Unix  system.   On  such	 a  system,  to	 link  a  file
       "hello.o":

	       ld -o <output> /lib/crt0.o hello.o -lc

       This  tells ld to produce a file	called output as the result of linking
       the file	"/lib/crt0.o" with "hello.o" and the library  "libc.a",	 which
       will come from the standard search directories.	(See the discussion of
       the -l option below.)

       Some of the command-line	options	to ld may be specified at any point in
       the command line.  However, options which refer to files, such as -l or
       -T, cause the file to be	read at	the point at which the option  appears
       in  the	command	 line, relative	to the object files and	other file op-
       tions.  Repeating non-file options with a different argument  will  ei-
       ther  have no further effect, or	override prior occurrences (those fur-
       ther to the left	on the command line) of	that  option.	Options	 which
       may  be meaningfully specified more than	once are noted in the descrip-
       tions below.

       Non-option arguments are	object files  or  archives  which  are	to  be
       linked  together.   They	 may follow, precede, or be mixed in with com-
       mand-line options, except that an  object  file	argument  may  not  be
       placed between an option	and its	argument.

       Usually	the  linker  is	invoked	with at	least one object file, but you
       can specify other forms of binary input files using  -l,	 -R,  and  the
       script  command	language.   If no binary input files at	all are	speci-
       fied, the linker	does not produce any output, and issues	the message No
       input files.

       If  the	linker	cannot recognize the format of an object file, it will
       assume that it is a linker script.  A script specified in this way aug-
       ments  the  main	 linker	 script	 used for the link (either the default
       linker script or	the one	specified by using -T).	 This feature  permits
       the  linker  to link against a file which appears to be an object or an
       archive,	but actually merely defines some symbol	values,	or  uses  "IN-
       PUT"  or	 "GROUP" to load other objects.	 Note that specifying a	script
       in this way merely augments the main linker script; use the  -T	option
       to replace the default linker script entirely.

       For  options whose names	are a single letter, option arguments must ei-
       ther follow the option letter without  intervening  whitespace,	or  be
       given  as  separate arguments immediately following the option that re-
       quires them.

       For options whose names are multiple letters, either one	 dash  or  two
       can   precede   the   option   name;  for  example,  -trace-symbol  and
       --trace-symbol are equivalent.  Note---there is one exception  to  this
       rule.   Multiple	 letter	 options  that start with a lower case 'o' can
       only be preceeded by two	dashes.	 This is to reduce confusion with  the
       -o  option.   So	for example -omagic sets the output file name to magic
       whereas --omagic	sets the NMAGIC	flag on	the output.

       Arguments to multiple-letter options must either	be separated from  the
       option  name by an equals sign, or be given as separate arguments imme-
       diately	following  the	option	that  requires	them.	For   example,
       --trace-symbol  foo  and	--trace-symbol=foo are equivalent.  Unique ab-
       breviations of the names	of multiple-letter options are accepted.

       Note---if the linker is being invoked indirectly, via a compiler	driver
       (e.g.  gcc) then	all the	linker command line options should be prefixed
       by -Wl, (or whatever is appropriate for the particular compiler driver)
       like this:

		 gcc -Wl,--startgroup foo.o bar.o -Wl,--endgroup

       This  is	 important,  because otherwise the compiler driver program may
       silently	drop the linker	options, resulting in a	bad link.

       Here is a table of the generic command line switches  accepted  by  the
       GNU linker:

       -akeyword
	   This	 option	is supported for HP/UX compatibility.  The keyword ar-
	   gument must be one of the  strings  archive,	 shared,  or  default.
	   -aarchive is	functionally equivalent	to -Bstatic, and the other two
	   keywords are	functionally equivalent	to -Bdynamic.  This option may
	   be used any number of times.

       -Aarchitecture
       --architecture=architecture
	   In  the  current  release of	ld, this option	is useful only for the
	   Intel 960 family of architectures.  In that ld  configuration,  the
	   architecture	argument identifies the	particular architecture	in the
	   960 family, enabling	some safeguards	and modifying the  archive-li-
	   brary search	path.

	   Future  releases  of	ld may support similar functionality for other
	   architecture	families.

       -b input-format
       --format=input-format
	   ld may be configured	to support more	than one kind of object	 file.
	   If  your  ld	 is  configured	this way, you can use the -b option to
	   specify the binary format for input object files that  follow  this
	   option  on the command line.	 Even when ld is configured to support
	   alternative object formats, you don't usually need to specify this,
	   as  ld should be configured to expect as a default input format the
	   most	usual format on	each machine.  input-format is a text  string,
	   the	name  of  a  particular	format supported by the	BFD libraries.
	   (You	can list the available binary formats with objdump -i.)

	   You may want	to use this option if you are linking  files  with  an
	   unusual  binary  format.  You can also use -b to switch formats ex-
	   plicitly (when linking object files of different formats),  by  in-
	   cluding -b input-format before each group of	object files in	a par-
	   ticular format.

	   The default format is taken from the	environment variable  "GNUTAR-
	   GET".

	   You	can also define	the input format from a	script,	using the com-
	   mand	"TARGET";

       -c MRI-commandfile
       --mri-script=MRI-commandfile
	   For compatibility with linkers produced by MRI, ld  accepts	script
	   files  written  in  an  alternate, restricted command language, de-
	   scribed in the MRI Compatible Script	Files section of GNU ld	 docu-
	   mentation.	Introduce MRI script files with	the option -c; use the
	   -T option to	run linker scripts written in the  general-purpose  ld
	   scripting language.	If MRI-cmdfile does not	exist, ld looks	for it
	   in the directories specified	by any -L options.

       -d
       -dc
       -dp These three options are equivalent; multiple	 forms	are  supported
	   for	compatibility with other linkers.  They	assign space to	common
	   symbols even	if a relocatable output	file is	specified  (with  -r).
	   The script command "FORCE_COMMON_ALLOCATION"	has the	same effect.

       -e entry
       --entry=entry
	   Use	entry  as  the explicit	symbol for beginning execution of your
	   program, rather than	the default entry point.  If there is no  sym-
	   bol	named  entry,  the linker will try to parse entry as a number,
	   and use that	as the entry address (the number will  be  interpreted
	   in  base  10;  you may use a	leading	0x for base 16,	or a leading 0
	   for base 8).

       -E
       --export-dynamic
	   When	creating a dynamically linked executable, add all  symbols  to
	   the	dynamic	 symbol	table.	The dynamic symbol table is the	set of
	   symbols which are visible from dynamic objects at run time.

	   If you do not use this option, the dynamic symbol table  will  nor-
	   mally  contain  only	those symbols which are	referenced by some dy-
	   namic object	mentioned in the link.

	   If you use "dlopen" to load a dynamic object	which needs  to	 refer
	   back	 to the	symbols	defined	by the program,	rather than some other
	   dynamic object, then	you will probably need to use this option when
	   linking the program itself.

	   You	can also use the version script	to control what	symbols	should
	   be added to the dynamic symbol table	if the output format  supports
	   it.	See the	description of --version-script	in @ref{VERSION}.

       -EB Link	big-endian objects.  This affects the default output format.

       -EL Link	 little-endian	objects.  This affects the default output for-
	   mat.

       -f
       --auxiliary name
	   When	creating an ELF	shared object, set the	internal  DT_AUXILIARY
	   field  to  the  specified name.  This tells the dynamic linker that
	   the symbol table of the shared object should	be used	as  an	auxil-
	   iary	filter on the symbol table of the shared object	name.

	   If  you later link a	program	against	this filter object, then, when
	   you run the program,	the dynamic linker will	see  the  DT_AUXILIARY
	   field.   If the dynamic linker resolves any symbols from the	filter
	   object, it will first check whether there is	a  definition  in  the
	   shared  object  name.   If there is one, it will be used instead of
	   the definition in the filter	object.	 The shared object  name  need
	   not	exist.	 Thus the shared object	name may be used to provide an
	   alternative implementation of certain functions, perhaps for	debug-
	   ging	or for machine specific	performance.

	   This	 option	may be specified more than once.  The DT_AUXILIARY en-
	   tries will be created in the	order in which they appear on the com-
	   mand	line.

       -F name
       --filter	name
	   When	 creating  an  ELF  shared  object, set	the internal DT_FILTER
	   field to the	specified name.	 This tells the	 dynamic  linker  that
	   the symbol table of the shared object which is being	created	should
	   be used as a	filter on the symbol table of the shared object	name.

	   If you later	link a program against this filter object, then,  when
	   you	run  the  program,  the	 dynamic linker	will see the DT_FILTER
	   field.  The dynamic linker will resolve symbols  according  to  the
	   symbol  table  of  the filter object	as usual, but it will actually
	   link	to the definitions found in the	shared object name.  Thus  the
	   filter  object  can	be used	to select a subset of the symbols pro-
	   vided by the	object name.

	   Some	older linkers used the	-F  option  throughout	a  compilation
	   toolchain for specifying object-file	format for both	input and out-
	   put object files.  The GNU linker uses other	 mechanisms  for  this
	   purpose:  the -b, --format, --oformat options, the "TARGET" command
	   in linker scripts, and the "GNUTARGET" environment  variable.   The
	   GNU	linker	will  ignore  the  -F  option when not creating	an ELF
	   shared object.

       -fini name
	   When	creating an ELF	executable or shared object,  call  NAME  when
	   the	executable or shared object is unloaded, by setting DT_FINI to
	   the address of the function.	 By default, the linker	 uses  "_fini"
	   as the function to call.

       -g  Ignored.  Provided for compatibility	with other tools.

       -Gvalue
       --gpsize=value
	   Set the maximum size	of objects to be optimized using the GP	regis-
	   ter to size.	 This is only meaningful for object file formats  such
	   as  MIPS  ECOFF which supports putting large	and small objects into
	   different sections.	This is	ignored	for other object file formats.

       -hname
       -soname=name
	   When	creating an ELF	shared	object,	 set  the  internal  DT_SONAME
	   field  to  the specified name.  When	an executable is linked	with a
	   shared object which has a DT_SONAME field, then when	the executable
	   is  run  the	 dynamic linker	will attempt to	load the shared	object
	   specified by	the DT_SONAME field rather than	 the  using  the  file
	   name	given to the linker.

       -i  Perform an incremental link (same as	option -r).

       -init name
	   When	 creating  an  ELF executable or shared	object,	call NAME when
	   the executable or shared object is loaded, by  setting  DT_INIT  to
	   the	address	 of the	function.  By default, the linker uses "_init"
	   as the function to call.

       -larchive
       --library=archive
	   Add archive file archive to the list	of files to link.  This	option
	   may	be used	any number of times.  ld will search its path-list for
	   occurrences of "libarchive.a" for every archive specified.

	   On systems which support shared libraries, ld may also  search  for
	   libraries  with  extensions	other than ".a".  Specifically,	on ELF
	   and SunOS systems, ld will search a directory for a library with an
	   extension  of  ".so"	 before	searching for one with an extension of
	   ".a".  By convention, a ".so" extension indicates a shared library.

	   The linker will search an archive only once,	at the location	 where
	   it is specified on the command line.	 If the	archive	defines	a sym-
	   bol which was undefined in some object which	 appeared  before  the
	   archive  on the command line, the linker will include the appropri-
	   ate file(s) from the	archive.  However, an undefined	symbol	in  an
	   object  appearing  later  on	 the  command  line will not cause the
	   linker to search the	archive	again.

	   See the -( option for a way to force	the linker to search  archives
	   multiple times.

	   You may list	the same archive multiple times	on the command line.

	   This	 type of archive searching is standard for Unix	linkers.  How-
	   ever, if you	are using ld on	AIX, note that it  is  different  from
	   the behaviour of the	AIX linker.

       -Lsearchdir
       --library-path=searchdir
	   Add path searchdir to the list of paths that	ld will	search for ar-
	   chive libraries and ld control scripts.  You	may  use  this	option
	   any	number of times.  The directories are searched in the order in
	   which they are specified on the command line.   Directories	speci-
	   fied	 on  the command line are searched before the default directo-
	   ries.  All -L options apply to all -l options,  regardless  of  the
	   order in which the options appear.

	   If  searchdir begins	with "=", then the "=" will be replaced	by the
	   sysroot prefix, a path specified when the linker is configured.

	   The default set of paths searched (without being specified with -L)
	   depends on which emulation mode ld is using,	and in some cases also
	   on how it was configured.

	   The paths  can  also	 be  specified	in  a  link  script  with  the
	   "SEARCH_DIR"	 command.  Directories specified this way are searched
	   at the point	in which the linker  script  appears  in  the  command
	   line.

       -memulation
	   Emulate  the	 emulation  linker.  You can list the available	emula-
	   tions with the --verbose or -V options.

	   If the -m option is not used,  the  emulation  is  taken  from  the
	   "LDEMULATION" environment variable, if that is defined.

	   Otherwise,  the  default  emulation depends upon how	the linker was
	   configured.

       -M
       --print-map
	   Print a link	map to the standard output.  A link map	 provides  in-
	   formation about the link, including the following:

	   *   Where object files and symbols are mapped into memory.

	   *   How common symbols are allocated.

	   *   All archive members included in the link, with a	mention	of the
	       symbol which caused the archive member to be brought in.

       -n
       --nmagic
	   Turn	off page  alignment  of	 sections,  and	 mark  the  output  as
	   "NMAGIC" if possible.

       -N
       --omagic
	   Set	the text and data sections to be readable and writable.	 Also,
	   do not page-align the data segment,	and  disable  linking  against
	   shared  libraries.	If the output format supports Unix style magic
	   numbers, mark the output as "OMAGIC".  Note:	 Although  a  writable
	   text	section	is allowed for PE-COFF targets,	it does	not conform to
	   the format specification published by Microsoft.

       --no-omagic
	   This	option negates most of the effects of the -N option.  It  sets
	   the text section to be read-only, and forces	the data segment to be
	   page-aligned.  Note - this option does not enable  linking  against
	   shared libraries.  Use -Bdynamic for	this.

       -o output
       --output=output
	   Use	output as the name for the program produced by ld; if this op-
	   tion	is not specified, the name a.out  is  used  by	default.   The
	   script command "OUTPUT" can also specify the	output file name.

       -O level
	   If  level  is  a  numeric values greater than zero ld optimizes the
	   output.  This might take significantly longer and therefore	proba-
	   bly should only be enabled for the final binary.

       -q
       --emit-relocs
	   Leave  relocation  sections and contents in fully linked exececuta-
	   bles.  Post link analysis and optimization tools may	need this  in-
	   formation in	order to perform correct modifications of executables.
	   This	results	in larger executables.

	   This	option is currently only supported on ELF platforms.

       -r
       --relocatable
	   Generate relocatable	output---i.e., generate	an  output  file  that
	   can	in  turn  serve	 as input to ld.  This is often	called partial
	   linking.  As	a side effect, in environments that  support  standard
	   Unix	 magic	numbers, this option also sets the output file's magic
	   number to "OMAGIC".	If this	option is not specified,  an  absolute
	   file	 is produced.  When linking C++	programs, this option will not
	   resolve references to constructors; to do that, use -Ur.

	   When	an input file does not have the	 same  format  as  the	output
	   file, partial linking is only supported if that input file does not
	   contain any relocations.  Different output formats can have further
	   restrictions; for example some "a.out"-based	formats	do not support
	   partial linking with	input files in other formats at	all.

	   This	option does the	same thing as -i.

       -R filename
       --just-symbols=filename
	   Read	symbol names and their addresses from filename,	but do not re-
	   locate  it  or  include  it in the output.  This allows your	output
	   file	to refer symbolically to absolute locations of memory  defined
	   in other programs.  You may use this	option more than once.

	   For	compatibility with other ELF linkers, if the -R	option is fol-
	   lowed by a directory	name, rather than a file name, it  is  treated
	   as the -rpath option.

       -s
       --strip-all
	   Omit	all symbol information from the	output file.

       -S
       --strip-debug
	   Omit	 debugger  symbol  information	(but not all symbols) from the
	   output file.

       -t
       --trace
	   Print the names of the input	files as ld processes them.

       -T scriptfile
       --script=scriptfile
	   Use scriptfile as the linker	script.	 This script replaces ld's de-
	   fault linker	script (rather than adding to it), so commandfile must
	   specify everything necessary	to describe  the  output  file.	    If
	   scriptfile  does not	exist in the current directory,	"ld" looks for
	   it in the directories specified by any preceding -L options.	  Mul-
	   tiple -T options accumulate.

       -u symbol
       --undefined=symbol
	   Force  symbol to be entered in the output file as an	undefined sym-
	   bol.	 Doing this may, for example, trigger  linking	of  additional
	   modules from	standard libraries.  -u	may be repeated	with different
	   option arguments to enter additional	undefined symbols.   This  op-
	   tion	is equivalent to the "EXTERN" linker script command.

       -Ur For	anything other than C++	programs, this option is equivalent to
	   -r: it generates relocatable	output---i.e., an output file that can
	   in  turn serve as input to ld.  When	linking	C++ programs, -Ur does
	   resolve references to constructors, unlike -r.  It does not work to
	   use	-Ur  on	 files	that were themselves linked with -Ur; once the
	   constructor table has been built, it	cannot be added	to.   Use  -Ur
	   only	for the	last partial link, and -r for the others.

       --unique[=SECTION]
	   Creates  a separate output section for every	input section matching
	   SECTION, or if the optional wildcard	SECTION	argument  is  missing,
	   for	every  orphan  input  section.	 An  orphan section is one not
	   specifically	mentioned in a linker script.  You may use this	option
	   multiple times on the command line;	It prevents the	normal merging
	   of input sections with the same name, overriding output section as-
	   signments in	a linker script.

       -v
       --version
       -V  Display  the	 version  number for ld.  The -V option	also lists the
	   supported emulations.

       -x
       --discard-all
	   Delete all local symbols.

       -X
       --discard-locals
	   Delete all temporary	local symbols.	For most targets, this is  all
	   local symbols whose names begin with	L.

       -y symbol
       --trace-symbol=symbol
	   Print  the  name of each linked file	in which symbol	appears.  This
	   option may be given any number of times.  On	 many  systems	it  is
	   necessary to	prepend	an underscore.

	   This	 option	 is  useful  when you have an undefined	symbol in your
	   link	but don't know where the reference is coming from.

       -Y path
	   Add path to the default library search path.	  This	option	exists
	   for Solaris compatibility.

       -z keyword
	   The recognized keywords are:

	   combreloc
	       Combines	multiple reloc sections	and sorts them to make dynamic
	       symbol lookup caching possible.

	   defs
	       Disallows undefined symbols in object files.  Undefined symbols
	       in shared libraries are still allowed.

	   initfirst
	       This  option  is	only meaningful	when building a	shared object.
	       It marks	the object so that its runtime initialization will oc-
	       cur  before  the	 runtime  initialization  of any other objects
	       brought into the	process	at the same time.  Similarly the  run-
	       time  finalization  of  the object will occur after the runtime
	       finalization of any other objects.

	   interpose
	       Marks the object	that its symbol	table  interposes  before  all
	       symbols but the primary executable.

	   loadfltr
	       Marks   the object that its filters be processed	immediately at
	       runtime.

	   muldefs
	       Allows multiple definitions.

	   nocombreloc
	       Disables	multiple reloc sections	combining.

	   nocopyreloc
	       Disables	production of copy relocs.

	   nodefaultlib
	       Marks the object	that the search	for dependencies of  this  ob-
	       ject will ignore	any default library search paths.

	   nodelete
	       Marks the object	shouldn't be unloaded at runtime.

	   nodlopen
	       Marks the object	not available to "dlopen".

	   nodump
	       Marks the object	can not	be dumped by "dldump".

	   now When  generating	 an  executable	 or shared library, mark it to
	       tell the	dynamic	linker to resolve all symbols when the program
	       is  started,  or	 when  the  shared  library is linked to using
	       dlopen, instead of deferring function call  resolution  to  the
	       point when the function is first	called.

	   origin
	       Marks the object	may contain $ORIGIN.

	   Other keywords are ignored for Solaris compatibility.

       -( archives -)
       --start-group archives --end-group
	   The archives	should be a list of archive files.  They may be	either
	   explicit file names,	or -l options.

	   The specified archives are searched repeatedly until	no  new	 unde-
	   fined  references  are  created.   Normally,	an archive is searched
	   only	once in	the order that it is specified on  the	command	 line.
	   If  a symbol	in that	archive	is needed to resolve an	undefined sym-
	   bol referred	to by an object	in an archive that  appears  later  on
	   the command line, the linker	would not be able to resolve that ref-
	   erence.  By grouping	the archives, they all be searched  repeatedly
	   until all possible references are resolved.

	   Using  this	option has a significant performance cost.  It is best
	   to use it only when there are unavoidable circular  references  be-
	   tween two or	more archives.

       --accept-unknown-input-arch
       --no-accept-unknown-input-arch
	   Tells the linker to accept input files whose	architecture cannot be
	   recognised.	The assumption is that the user	knows  what  they  are
	   doing  and deliberately wants to link in these unknown input	files.
	   This	was the	default	behaviour of the linker, before	release	 2.14.
	   The	default	 behaviour from	release	2.14 onwards is	to reject such
	   input files,	and so the --accept-unknown-input-arch option has been
	   added to restore the	old behaviour.

       --as-needed
       --no-as-needed
	   This	 option	 affects ELF DT_NEEDED tags for	dynamic	libraries men-
	   tioned on the command line after the	--as-needed option.  Normally,
	   the	linker	will add a DT_NEEDED tag for each dynamic library men-
	   tioned on the command line, regardless of whether  the  library  is
	   actually needed. --as-needed	causes DT_NEEDED tags to only be emit-
	   ted for libraries that satisfy some reference from regular objects.
	   --no-as-needed restores the default behaviour.

       -assert keyword
	   This	option is ignored for SunOS compatibility.

       -Bdynamic
       -dy
       -call_shared
	   Link	 against  dynamic libraries.  This is only meaningful on plat-
	   forms for which shared libraries are	 supported.   This  option  is
	   normally  the default on such platforms.  The different variants of
	   this	option are for compatibility with various  systems.   You  may
	   use	this option multiple times on the command line:	it affects li-
	   brary searching for -l options which	follow it.

       -Bgroup
	   Set the "DF_1_GROUP"	flag in	the "DT_FLAGS_1" entry in the  dynamic
	   section.   This causes the runtime linker to	handle lookups in this
	   object and its dependencies to be performed only inside the	group.
	   --unresolved-symbols=report-all  is	implied.   This	option is only
	   meaningful on ELF platforms which support shared libraries.

       -Bstatic
       -dn
       -non_shared
       -static
	   Do not link against shared libraries.  This is only	meaningful  on
	   platforms  for which	shared libraries are supported.	 The different
	   variants of this option are for compatibility with various systems.
	   You	may use	this option multiple times on the command line:	it af-
	   fects library searching for -l options which	follow it.   This  op-
	   tion	also implies --unresolved-symbols=report-all.

       -Bsymbolic
	   When	 creating  a shared library, bind references to	global symbols
	   to the definition within the	shared library,	if any.	 Normally,  it
	   is  possible	for a program linked against a shared library to over-
	   ride	the definition within the shared library.  This	option is only
	   meaningful on ELF platforms which support shared libraries.

       --check-sections
       --no-check-sections
	   Asks	the linker not to check	section	addresses after	they have been
	   assigned to see if there any	overlaps.  Normally  the  linker  will
	   perform  this  check,  and if it finds any overlaps it will produce
	   suitable error messages.  The linker	does know about, and does make
	   allowances  for sections in overlays.  The default behaviour	can be
	   restored by using the command line switch --check-sections.

       --cref
	   Output a cross reference table.  If a linker	map file is being gen-
	   erated, the cross reference table is	printed	to the map file.  Oth-
	   erwise, it is printed on the	standard output.

	   The format of the table is intentionally simple, so that it may  be
	   easily processed by a script	if necessary.  The symbols are printed
	   out,	sorted by name.	 For each symbol, a  list  of  file  names  is
	   given.   If the symbol is defined, the first	file listed is the lo-
	   cation of the definition.  The remaining files  contain  references
	   to the symbol.

       --no-define-common
	   This	option inhibits	the assignment of addresses to common symbols.
	   The script command "INHIBIT_COMMON_ALLOCATION" has the same effect.

	   The --no-define-common option allows	decoupling the decision	to as-
	   sign	addresses to Common symbols from the choice of the output file
	   type; otherwise a non-Relocatable output type forces	assigning  ad-
	   dresses  to Common symbols.	Using --no-define-common allows	Common
	   symbols that	are referenced from a shared library  to  be  assigned
	   addresses only in the main program.	This eliminates	the unused du-
	   plicate space in the	shared library,	and also prevents any possible
	   confusion over resolving to the wrong duplicate when	there are many
	   dynamic modules with	specialized search paths  for  runtime	symbol
	   resolution.

       --defsym	symbol=expression
	   Create  a global symbol in the output file, containing the absolute
	   address given by expression.	 You may use this option as many times
	   as  necessary  to  define  multiple symbols in the command line.  A
	   limited form	of arithmetic is supported for the expression in  this
	   context:  you may give a hexadecimal	constant or the	name of	an ex-
	   isting symbol, or use "+" and "-" to	add  or	 subtract  hexadecimal
	   constants or	symbols.  If you need more elaborate expressions, con-
	   sider using the linker command language from	a script.  Note: there
	   should  be  no white	space between symbol, the equals sign (``=''),
	   and expression.

       --demangle[=style]
       --no-demangle
	   These options control whether to demangle  symbol  names  in	 error
	   messages and	other output.  When the	linker is told to demangle, it
	   tries to present symbol names in  a	readable  fashion:  it	strips
	   leading underscores if they are used	by the object file format, and
	   converts C++	mangled	symbol names into user readable	 names.	  Dif-
	   ferent  compilers have different mangling styles.  The optional de-
	   mangling style argument can be used to choose an appropriate	deman-
	   gling style for your	compiler.  The linker will demangle by default
	   unless the environment variable COLLECT_NO_DEMANGLE is set.	 These
	   options may be used to override the default.

       --dynamic-linker	file
	   Set	the  name of the dynamic linker.  This is only meaningful when
	   generating dynamically linked ELF executables.  The default dynamic
	   linker is normally correct; don't use this unless you know what you
	   are doing.

       --embedded-relocs
	   This	option is only meaningful when linking MIPS embedded PIC code,
	   generated  by the -membedded-pic option to the GNU compiler and as-
	   sembler.  It	causes the linker to create a table which may be  used
	   at runtime to relocate any data which was statically	initialized to
	   pointer values.  See	the code in testsuite/ld-empic for details.

       --fatal-warnings
	   Treat all warnings as errors.

       --force-exe-suffix
	   Make	sure that an output file has a .exe suffix.

	   If a	successfully built fully linked	output file does  not  have  a
	   ".exe"  or ".dll" suffix, this option forces	the linker to copy the
	   output file to one of the same name with a ".exe" suffix. This  op-
	   tion	 is useful when	using unmodified Unix makefiles	on a Microsoft
	   Windows host, since some versions of	Windows	won't run an image un-
	   less	it ends	in a ".exe" suffix.

       --no-gc-sections
       --gc-sections
	   Enable  garbage collection of unused	input sections.	 It is ignored
	   on targets that do not support this option.	 This  option  is  not
	   compatible  with  -r,  nor  should it be used with dynamic linking.
	   The default behaviour (of not performing this  garbage  collection)
	   can be restored by specifying --no-gc-sections on the command line.

       --help
	   Print  a summary of the command-line	options	on the standard	output
	   and exit.

       --target-help
	   Print a summary of all target specific options on the standard out-
	   put and exit.

       -Map mapfile
	   Print  a  link map to the file mapfile.  See	the description	of the
	   -M option, above.

       --no-keep-memory
	   ld normally optimizes for speed over	memory usage  by  caching  the
	   symbol  tables  of  input files in memory.  This option tells ld to
	   instead optimize for	memory usage, by rereading the	symbol	tables
	   as  necessary.  This	may be required	if ld runs out of memory space
	   while linking a large executable.

       --no-undefined
       -z defs
	   Report unresolved symbol  references	 from  regular	object	files.
	   This	 is  done even if the linker is	creating a non-symbolic	shared
	   library.  The switch	--[no-]allow-shlib-undefined controls the  be-
	   haviour  for	 reporting  unresolved	references found in shared li-
	   braries being linked	in.

       --allow-multiple-definition
       -z muldefs
	   Normally when a symbol is defined multiple times, the  linker  will
	   report  a fatal error. These	options	allow multiple definitions and
	   the first definition	will be	used.

       --allow-shlib-undefined
       --no-allow-shlib-undefined
	   Allows (the default)	or disallows undefined symbols in  shared  li-
	   braries.   This  switch is similar to --no-undefined	except that it
	   determines the behaviour when the undefined symbols are in a	shared
	   library  rather than	a regular object file.	It does	not affect how
	   undefined symbols in	regular	object files are handled.

	   The reason that --allow-shlib-undefined is the default is that  the
	   shared  library being specified at link time	may not	be the same as
	   the one that	is available at	load time, so the symbols might	 actu-
	   ally	 be resolvable at load time.  Plus there are some systems, (eg
	   BeOS) where undefined symbols in shared libraries is	normal.	  (The
	   kernel  patches  them at load time to select	which function is most
	   appropriate for the current architecture.  This is used for example
	   to  dynamically select an appropriate memset	function).  Apparently
	   it is also normal for HPPA shared libraries to have undefined  sym-
	   bols.

       --no-undefined-version
	   Normally  when  a  symbol has an undefined version, the linker will
	   ignore it. This option disallows symbols with undefined version and
	   a fatal error will be issued	instead.

       --no-warn-mismatch
	   Normally  ld	 will  give an error if	you try	to link	together input
	   files that are mismatched for some  reason,	perhaps	 because  they
	   have	 been compiled for different processors	or for different endi-
	   annesses.  This option tells	ld that	it should silently permit such
	   possible  errors.   This  option  should only be used with care, in
	   cases when you have taken some special action that ensures that the
	   linker errors are inappropriate.

       --no-whole-archive
	   Turn	 off  the  effect of the --whole-archive option	for subsequent
	   archive files.

       --noinhibit-exec
	   Retain the executable output	file  whenever	it  is	still  usable.
	   Normally,  the linker will not produce an output file if it encoun-
	   ters	errors during the link process;	it exits  without  writing  an
	   output file when it issues any error	whatsoever.

       -nostdlib
	   Only	search library directories explicitly specified	on the command
	   line.  Library directories specified	in linker  scripts  (including
	   linker scripts specified on the command line) are ignored.

       --oformat output-format
	   ld  may be configured to support more than one kind of object file.
	   If your ld is configured this way, you can use the --oformat	option
	   to specify the binary format	for the	output object file.  Even when
	   ld is configured to support alternative object formats,  you	 don't
	   usually need	to specify this, as ld should be configured to produce
	   as a	default	output format the most usual format on	each  machine.
	   output-format  is  a	 text  string, the name	of a particular	format
	   supported by	the BFD	libraries.  (You can list the available	binary
	   formats  with  objdump -i.)	The script command "OUTPUT_FORMAT" can
	   also	specify	the output format, but this option overrides it.

       -pie
       --pic-executable
	   Create a position independent executable.  This is  currently  only
	   supported  on  ELF platforms.  Position independent executables are
	   similar to shared libraries in that they are	relocated by  the  dy-
	   namic  linker to the	virtual	address	the OS chooses for them	(which
	   can vary between invocations).  Like	normal dynamically linked exe-
	   cutables they can be	executed and symbols defined in	the executable
	   cannot be overridden	by shared libraries.

       -qmagic
	   This	option is ignored for Linux compatibility.

       -Qy This	option is ignored for SVR4 compatibility.

       --relax
	   An option with machine dependent effects.  This option is only sup-
	   ported on a few targets.

	   On some platforms, the --relax option performs global optimizations
	   that	become possible	when the linker	 resolves  addressing  in  the
	   program,  such  as  relaxing	address	modes and synthesizing new in-
	   structions in the output object file.

	   On some platforms these link	time  global  optimizations  may  make
	   symbolic debugging of the resulting executable impossible.  This is
	   known to be the case	for the	Matsushita MN10200 and MN10300	family
	   of processors.

	   On  platforms where this is not supported, --relax is accepted, but
	   ignored.

       --retain-symbols-file filename
	   Retain only the symbols listed in the file filename,	discarding all
	   others.   filename  is simply a flat	file, with one symbol name per
	   line.  This option is especially useful in  environments  (such  as
	   VxWorks)  where  a  large global symbol table is accumulated	gradu-
	   ally, to conserve run-time memory.

	   --retain-symbols-file does not discard undefined symbols,  or  sym-
	   bols	needed for relocations.

	   You	may  only  specify  --retain-symbols-file  once	in the command
	   line.  It overrides -s and -S.

       -rpath dir
	   Add a directory to the runtime library search path.	This  is  used
	   when	linking	an ELF executable with shared objects.	All -rpath ar-
	   guments are concatenated and	passed to the  runtime	linker,	 which
	   uses	 them  to locate shared	objects	at runtime.  The -rpath	option
	   is also used	when locating  shared  objects	which  are  needed  by
	   shared objects explicitly included in the link; see the description
	   of the -rpath-link option.  If -rpath is not	used when  linking  an
	   ELF	 executable,   the   contents	of  the	 environment  variable
	   "LD_RUN_PATH" will be used if it is defined.

	   The -rpath option may also be used on SunOS.	 By default, on	SunOS,
	   the	linker	will form a runtime search patch out of	all the	-L op-
	   tions it is given.  If a -rpath option is used, the runtime	search
	   path	 will be formed	exclusively using the -rpath options, ignoring
	   the -L options.  This can be	useful when using gcc, which adds many
	   -L options which may	be on NFS mounted filesystems.

	   For	compatibility with other ELF linkers, if the -R	option is fol-
	   lowed by a directory	name, rather than a file name, it  is  treated
	   as the -rpath option.

       -rpath-link DIR
	   When	 using	ELF  or	SunOS, one shared library may require another.
	   This	happens	when an	"ld -shared" link includes a shared library as
	   one of the input files.

	   When	  the  linker  encounters  such	 a  dependency	when  doing  a
	   non-shared, non-relocatable link, it	will automatically try to  lo-
	   cate	 the required shared library and include it in the link, if it
	   is not included explicitly.	In such	a case,	the -rpath-link	option
	   specifies  the first	set of directories to search.  The -rpath-link
	   option may specify a	sequence of directory names either by specify-
	   ing	a  list	of names separated by colons, or by appearing multiple
	   times.

	   This	option should be used with caution as it overrides the	search
	   path	 that  may  have  been hard compiled into a shared library. In
	   such	a case it is  possible	to  use	 unintentionally  a  different
	   search path than the	runtime	linker would do.

	   The	linker	uses  the  following  search  paths to locate required
	   shared libraries.

	   1.  Any directories specified by -rpath-link	options.

	   2.  Any directories specified by -rpath  options.   The  difference
	       between -rpath and -rpath-link is that directories specified by
	       -rpath options are included in the executable and used at  run-
	       time,  whereas the -rpath-link option is	only effective at link
	       time. It	is for the native linker only.

	   3.  On an ELF system, if the	-rpath and "rpath-link"	 options  were
	       not  used,  search  the	contents  of  the environment variable
	       "LD_RUN_PATH". It is for	the native linker only.

	   4.  On SunOS, if the	-rpath option was not used, search any	direc-
	       tories specified	using -L options.

	   5.  For  a  native linker, the contents of the environment variable
	       "LD_LIBRARY_PATH".

	   6.  For a native ELF	linker,	the  directories  in  "DT_RUNPATH"  or
	       "DT_RPATH"  of  a  shared  library  are searched	for shared li-
	       braries needed by it. The "DT_RPATH"  entries  are  ignored  if
	       "DT_RUNPATH" entries exist.

	   7.  The default directories,	normally /lib and /usr/lib.

	   8.  For   a	 native	  linker   on  an  ELF	system,	 if  the  file
	       /etc/ld.so.conf exists, the list	of directories found  in  that
	       file.

	   If  the required shared library is not found, the linker will issue
	   a warning and continue with the link.

       -shared
       -Bshareable
	   Create a shared library.  This is currently only supported on  ELF,
	   XCOFF and SunOS platforms.  On SunOS, the linker will automatically
	   create a shared library if the -e option is not used	and there  are
	   undefined symbols in	the link.

       --sort-common
	   This	 option	 tells	ld  to sort the	common symbols by size when it
	   places them in the appropriate output sections.  First come all the
	   one	byte  symbols,	then all the two byte, then all	the four byte,
	   and then everything else.  This is to prevent gaps between  symbols
	   due to alignment constraints.

       --split-by-file [size]
	   Similar  to	--split-by-reloc  but creates a	new output section for
	   each	input file when	size is	reached.  size defaults	to a size of 1
	   if not given.

       --split-by-reloc	[count]
	   Tries  to creates extra sections in the output file so that no sin-
	   gle output section in the file contains  more  than	count  reloca-
	   tions.   This  is useful when generating huge relocatable files for
	   downloading into certain real time kernels  with  the  COFF	object
	   file	 format;  since	 COFF cannot represent more than 65535 reloca-
	   tions in a single section.  Note that this will fail	to  work  with
	   object  file	 formats which do not support arbitrary	sections.  The
	   linker will not split up individual input sections for  redistribu-
	   tion, so if a single	input section contains more than count reloca-
	   tions one output section will contain that many relocations.	 count
	   defaults to a value of 32768.

       --stats
	   Compute  and	 display statistics about the operation	of the linker,
	   such	as execution time and memory usage.

       --traditional-format
	   For some targets, the output	of ld is different in some  ways  from
	   the output of some existing linker.	This switch requests ld	to use
	   the traditional format instead.

	   For example,	on SunOS, ld combines duplicate	entries	in the	symbol
	   string table.  This can reduce the size of an output	file with full
	   debugging information by over 30 percent.  Unfortunately, the SunOS
	   "dbx"  program  can	not  read  the resulting program ("gdb"	has no
	   trouble).  The --traditional-format switch tells ld to not  combine
	   duplicate entries.

       --section-start sectionname=org
	   Locate  a  section in the output file at the	absolute address given
	   by org.  You	may use	this option as many times as necessary to  lo-
	   cate	 multiple  sections in the command line.  org must be a	single
	   hexadecimal integer;	for compatibility with other linkers, you  may
	   omit	 the  leading  0x  usually associated with hexadecimal values.
	   Note: there should be  no  white  space  between  sectionname,  the
	   equals sign (``=''),	and org.

       -Tbss org
       -Tdata org
       -Ttext org
	   Same	 as  --section-start,  with  ".bss", ".data" or	".text"	as the
	   sectionname.

       --unresolved-symbols=method
	   Determine how to handle unresolved symbols.	There are four	possi-
	   ble values for method:

	   ignore-all
	       Do not report any unresolved symbols.

	   report-all
	       Report all unresolved symbols.  This is the default.

	   ignore-in-object-files
	       Report  unresolved  symbols  that  are  contained in shared li-
	       braries,	but ignore them	 if  they  come	 from  regular	object
	       files.

	   ignore-in-shared-libs
	       Report  unresolved symbols that come from regular object	files,
	       but ignore them if they come from shared	libraries.   This  can
	       be  useful  when	creating a dynamic binary and it is known that
	       all the shared libraries	that it	should be referencing are  in-
	       cluded on the linker's command line.

	   The	behaviour  for	shared libraries on their own can also be con-
	   trolled by the --[no-]allow-shlib-undefined option.

	   Normally the	linker will generate an	error  message	for  each  re-
	   ported  unresolved  symbol but the option --warn-unresolved-symbols
	   can change this to a	warning.

       --dll-verbose
       --verbose
	   Display the version number for ld and list  the  linker  emulations
	   supported.	Display	 which	input  files can and cannot be opened.
	   Display the linker script being used	by the linker.

       --version-script=version-scriptfile
	   Specify the name of a version script	to the linker.	This is	 typi-
	   cally used when creating shared libraries to	specify	additional in-
	   formation about the version hierarchy for the  library  being  cre-
	   ated.   This	 option	is only	meaningful on ELF platforms which sup-
	   port	shared libraries.

       --warn-common
	   Warn	when a common symbol is	combined with another common symbol or
	   with	 a symbol definition.  Unix linkers allow this somewhat	sloppy
	   practise, but linkers on some other operating systems do not.  This
	   option  allows you to find potential	problems from combining	global
	   symbols.  Unfortunately, some C libraries use this practise,	so you
	   may	get some warnings about	symbols	in the libraries as well as in
	   your	programs.

	   There are three kinds of global symbols, illustrated	here by	C  ex-
	   amples:

	   int i = 1;
	       A definition, which goes	in the initialized data	section	of the
	       output file.

	   extern int i;
	       An undefined reference, which does not allocate	space.	 There
	       must be either a	definition or a	common symbol for the variable
	       somewhere.

	   int i;
	       A common	symbol.	 If there are only (one	or more)  common  sym-
	       bols  for a variable, it	goes in	the uninitialized data area of
	       the output file.	 The linker merges multiple common symbols for
	       the same	variable into a	single symbol.	If they	are of differ-
	       ent sizes, it picks the largest size.  The linker turns a  com-
	       mon  symbol into	a declaration, if there	is a definition	of the
	       same variable.

	   The --warn-common option can	produce	five kinds of warnings.	  Each
	   warning consists of a pair of lines:	the first describes the	symbol
	   just	encountered, and the second describes the previous symbol  en-
	   countered  with the same name.  One or both of the two symbols will
	   be a	common symbol.

	   1.  Turning a common	symbol into a reference, because there is  al-
	       ready a definition for the symbol.

		       <file>(<section>): warning: common of `<symbol>'
			  overridden by	definition
		       <file>(<section>): warning: defined here

	   2.  Turning a common	symbol into a reference, because a later defi-
	       nition for the symbol is	encountered.  This is the same as  the
	       previous	 case,	except	that  the symbols are encountered in a
	       different order.

		       <file>(<section>): warning: definition of `<symbol>'
			  overriding common
		       <file>(<section>): warning: common is here

	   3.  Merging a common	symbol with a previous same-sized common  sym-
	       bol.

		       <file>(<section>): warning: multiple common
			  of `<symbol>'
		       <file>(<section>): warning: previous common is here

	   4.  Merging a common	symbol with a previous larger common symbol.

		       <file>(<section>): warning: common of `<symbol>'
			  overridden by	larger common
		       <file>(<section>): warning: larger common is here

	   5.  Merging	a common symbol	with a previous	smaller	common symbol.
	       This is the same	as the previous	case, except that the  symbols
	       are encountered in a different order.

		       <file>(<section>): warning: common of `<symbol>'
			  overriding smaller common
		       <file>(<section>): warning: smaller common is here

       --warn-constructors
	   Warn	 if any	global constructors are	used.  This is only useful for
	   a few object	file formats.  For  formats  like  COFF	 or  ELF,  the
	   linker can not detect the use of global constructors.

       --warn-multiple-gp
	   Warn	 if  multiple global pointer values are	required in the	output
	   file.  This is only meaningful for certain processors, such as  the
	   Alpha.  Specifically, some processors put large-valued constants in
	   a special section.  A special register (the global pointer)	points
	   into	 the  middle  of this section, so that constants can be	loaded
	   efficiently via a base-register relative  addressing	 mode.	 Since
	   the	offset	in base-register relative mode is fixed	and relatively
	   small (e.g.,	16 bits), this limits the maximum size of the constant
	   pool.  Thus,	in large programs, it is often necessary to use	multi-
	   ple global pointer values in	order to be able to address all	possi-
	   ble	constants.  This option	causes a warning to be issued whenever
	   this	case occurs.

       --warn-once
	   Only	warn once for each undefined symbol, rather than once per mod-
	   ule which refers to it.

       --warn-section-align
	   Warn	 if  the  address  of  an output section is changed because of
	   alignment.  Typically, the alignment	will be	set by an  input  sec-
	   tion.  The address will only	be changed if it not explicitly	speci-
	   fied; that is, if the "SECTIONS" command does not specify  a	 start
	   address for the section.

       --warn-unresolved-symbols
	   If  the linker is going to report an	unresolved symbol (see the op-
	   tion	--unresolved-symbols) it  will	normally  generate  an	error.
	   This	option makes it	generate a warning instead.

       --error-unresolved-symbols
	   This	 restores  the linker's	default	behaviour of generating	errors
	   when	it is reporting	unresolved symbols.

       --whole-archive
	   For	each  archive  mentioned  on  the  command  line   after   the
	   --whole-archive option, include every object	file in	the archive in
	   the link, rather than searching the archive for the required	object
	   files.  This	is normally used to turn an archive file into a	shared
	   library, forcing every object  to  be  included  in	the  resulting
	   shared library.  This option	may be used more than once.

	   Two	notes when using this option from gcc: First, gcc doesn't know
	   about this option, so you have to use -Wl,-whole-archive.   Second,
	   don't  forget  to  use -Wl,-no-whole-archive	after your list	of ar-
	   chives, because gcc will add	its own	list of	archives to your  link
	   and you may not want	this flag to affect those as well.

       --wrap symbol
	   Use a wrapper function for symbol.  Any undefined reference to sym-
	   bol will be resolved	to "__wrap_symbol".  Any  undefined  reference
	   to "__real_symbol" will be resolved to symbol.

	   This	 can  be used to provide a wrapper for a system	function.  The
	   wrapper function should be called "__wrap_symbol".  If it wishes to
	   call	the system function, it	should call "__real_symbol".

	   Here	is a trivial example:

		   void	*
		   __wrap_malloc (size_t c)
		   {
		     printf ("malloc called with %zu\n", c);
		     return __real_malloc (c);
		   }

	   If you link other code with this file using --wrap malloc, then all
	   calls to "malloc" will call the function  "__wrap_malloc"  instead.
	   The	call  to "__real_malloc" in "__wrap_malloc" will call the real
	   "malloc" function.

	   You may wish	to provide a "__real_malloc" function as well, so that
	   links  without the --wrap option will succeed.  If you do this, you
	   should not put the definition of "__real_malloc" in the  same  file
	   as  "__wrap_malloc";	 if you	do, the	assembler may resolve the call
	   before the linker has a chance to wrap it to	"malloc".

       --enable-new-dtags
       --disable-new-dtags
	   This	linker can create the new dynamic tags in ELF. But  the	 older
	   ELF	 systems  may  not  understand	them.  If  you	specify	 --en-
	   able-new-dtags, the dynamic tags will be created as needed.	If you
	   specify  --disable-new-dtags,  no new dynamic tags will be created.
	   By default, the new dynamic tags are	not created. Note  that	 those
	   options are only available for ELF systems.

       The i386	PE linker supports the -shared option, which causes the	output
       to be a dynamically linked library  (DLL)  instead  of  a  normal  exe-
       cutable.	  You should name the output "*.dll" when you use this option.
       In addition, the	linker fully  supports	the  standard  "*.def"	files,
       which  may  be specified	on the linker command line like	an object file
       (in fact, it should precede archives it exports symbols from, to	ensure
       that they get linked in,	just like a normal object file).

       In  addition  to	 the options common to all targets, the	i386 PE	linker
       support additional command line options that are	specific to  the  i386
       PE target.  Options that	take values may	be separated from their	values
       by either a space or an equals sign.

       --add-stdcall-alias
	   If given, symbols with a stdcall suffix (@nn) will be exported  as-
	   is  and also	with the suffix	stripped.  [This option	is specific to
	   the i386 PE targeted	port of	the linker]

       --base-file file
	   Use file as the name	of a file in which to save the base  addresses
	   of  all  the	 relocations  needed for generating DLLs with dlltool.
	   [This is an i386 PE specific	option]

       --dll
	   Create a DLL	instead	of a regular executable.   You	may  also  use
	   -shared  or	specify	a "LIBRARY" in a given ".def" file.  [This op-
	   tion	is specific to the i386	PE targeted port of the	linker]

       --enable-stdcall-fixup
       --disable-stdcall-fixup
	   If the link finds a symbol that it cannot resolve, it will  attempt
	   to  do ``fuzzy linking'' by looking for another defined symbol that
	   differs only	in the format of the symbol name  (cdecl  vs  stdcall)
	   and will resolve that symbol	by linking to the match.  For example,
	   the undefined  symbol  "_foo"  might	 be  linked  to	 the  function
	   "_foo@12", or the undefined symbol "_bar@16"	might be linked	to the
	   function "_bar".  When the linker does this,	it prints  a  warning,
	   since  it normally should have failed to link, but sometimes	import
	   libraries generated from third-party	dlls may need this feature  to
	   be  usable.	If you specify --enable-stdcall-fixup, this feature is
	   fully enabled and warnings are not printed.	If you specify	--dis-
	   able-stdcall-fixup,	this  feature  is disabled and such mismatches
	   are considered to be	errors.	 [This option is specific to the  i386
	   PE targeted port of the linker]

       --export-all-symbols
	   If  given,  all  global  symbols in the objects used	to build a DLL
	   will	be exported by the DLL.	 Note that  this  is  the  default  if
	   there otherwise wouldn't be any exported symbols.  When symbols are
	   explicitly exported via DEF files or	implicitly exported via	 func-
	   tion	 attributes, the default is to not export anything else	unless
	   this	option is given.  Note that the	symbols	"DllMain@12",  "DllEn-
	   tryPoint@0",	 "DllMainCRTStartup@12",  and "impure_ptr" will	not be
	   automatically exported.  Also, symbols  imported  from  other  DLLs
	   will	 not be	re-exported, nor will symbols specifying the DLL's in-
	   ternal layout such as those beginning with "_head_" or ending  with
	   "_iname".  In addition, no symbols from "libgcc", "libstd++", "lib-
	   mingw32", or	"crtX.o" will be exported.  Symbols whose names	 begin
	   with	 "__rtti_"  or "__builtin_" will not be	exported, to help with
	   C++ DLLs.  Finally, there is	an extensive  list  of	cygwin-private
	   symbols  that  are  not  exported  (obviously, this applies on when
	   building DLLs for  cygwin  targets).	  These	 cygwin-excludes  are:
	   "_cygwin_dll_entry@12",  "_cygwin_crt0_common@8",  "_cygwin_noncyg-
	   win_dll_entry@12",  "_fmode",  "_impure_ptr",  "cygwin_attach_dll",
	   "cygwin_premain0",	"cygwin_premain1",   "cygwin_premain2",	 "cyg-
	   win_premain3", and "environ".  [This	option is specific to the i386
	   PE targeted port of the linker]

       --exclude-symbols symbol,symbol,...
	   Specifies  a	 list of symbols which should not be automatically ex-
	   ported.  The	symbol names may be delimited  by  commas  or  colons.
	   [This  option  is  specific	to  the	 i386  PE targeted port	of the
	   linker]

       --exclude-libs lib,lib,...
	   Specifies a list of archive libraries from which symbols should not
	   be  automatically  exported.	 The library names may be delimited by
	   commas or colons.  Specifying "--exclude-libs ALL" excludes symbols
	   in  all archive libraries from automatic export. Symbols explicitly
	   listed in a .def file are still exported, regardless	 of  this  op-
	   tion.  [This	option is specific to the i386 PE targeted port	of the
	   linker]

       --file-alignment
	   Specify the file alignment.	Sections in the	file will always begin
	   at  file offsets which are multiples	of this	number.	 This defaults
	   to 512.  [This option is specific to	the i386 PE targeted  port  of
	   the linker]

       --heap reserve
       --heap reserve,commit
	   Specify  the	amount of memory to reserve (and optionally commit) to
	   be used as heap for this program.  The default is 1Mb reserved,  4K
	   committed.	[This  option is specific to the i386 PE targeted port
	   of the linker]

       --image-base value
	   Use value as	the base address of your program or dll.  This is  the
	   lowest  memory  location that will be used when your	program	or dll
	   is loaded.  To reduce the need to relocate and improve  performance
	   of  your dlls, each should have a unique base address and not over-
	   lap any other dlls.	The default is 0x400000	for  executables,  and
	   0x10000000  for dlls.  [This	option is specific to the i386 PE tar-
	   geted port of the linker]

       --kill-at
	   If given, the stdcall suffixes (@nn)	will be	stripped from  symbols
	   before  they	are exported.  [This option is specific	to the i386 PE
	   targeted port of the	linker]

       --major-image-version value
	   Sets	the major number of the	``image	 version''.   Defaults	to  1.
	   [This  option  is  specific	to  the	 i386  PE targeted port	of the
	   linker]

       --major-os-version value
	   Sets	the major number of the	``os version''.	 Defaults to 4.	 [This
	   option is specific to the i386 PE targeted port of the linker]

       --major-subsystem-version value
	   Sets	the major number of the	``subsystem version''.	Defaults to 4.
	   [This option	is specific to	the  i386  PE  targeted	 port  of  the
	   linker]

       --minor-image-version value
	   Sets	 the  minor  number  of	the ``image version''.	Defaults to 0.
	   [This option	is specific to	the  i386  PE  targeted	 port  of  the
	   linker]

       --minor-os-version value
	   Sets	the minor number of the	``os version''.	 Defaults to 0.	 [This
	   option is specific to the i386 PE targeted port of the linker]

       --minor-subsystem-version value
	   Sets	the minor number of the	``subsystem version''.	Defaults to 0.
	   [This  option  is  specific	to  the	 i386  PE targeted port	of the
	   linker]

       --output-def file
	   The linker will create the file file	which will contain a DEF  file
	   corresponding  to  the DLL the linker is generating.	 This DEF file
	   (which should be called "*.def") may	be used	to  create  an	import
	   library  with  "dlltool" or may be used as a	reference to automati-
	   cally or implicitly exported	symbols.  [This	option is specific  to
	   the i386 PE targeted	port of	the linker]

       --out-implib file
	   The	linker	will create the	file file which	will contain an	import
	   lib corresponding to	the DLL	the linker is generating. This	import
	   lib	(which should be called	"*.dll.a" or "*.a" may be used to link
	   clients against the generated DLL; this behaviour makes it possible
	   to  skip  a separate	"dlltool" import library creation step.	 [This
	   option is specific to the i386 PE targeted port of the linker]

       --enable-auto-image-base
	   Automatically choose	the image base for DLLs, unless	one is	speci-
	   fied	 using the "--image-base" argument.  By	using a	hash generated
	   from	the dllname to create unique image bases for each DLL, in-mem-
	   ory	collisions  and	 relocations which can delay program execution
	   are avoided.	 [This option is specific to the i386 PE targeted port
	   of the linker]

       --disable-auto-image-base
	   Do  not automatically generate a unique image base.	If there is no
	   user-specified image	base ("--image-base") then  use	 the  platform
	   default.   [This option is specific to the i386 PE targeted port of
	   the linker]

       --dll-search-prefix string
	   When	linking	dynamically to a dll without an	import library,	search
	   for	"<string><basename>.dll" in preference to "lib<basename>.dll".
	   This	behaviour allows easy distinction between DLLs built  for  the
	   various  "subplatforms":  native,  cygwin,  uwin, pw, etc.  For in-
	   stance, cygwin DLLs typically use "--dll-search-prefix=cyg".	 [This
	   option is specific to the i386 PE targeted port of the linker]

       --enable-auto-import
	   Do  sophisticated  linking of "_symbol" to "__imp__symbol" for DATA
	   imports from	DLLs, and create the necessary thunking	 symbols  when
	   building the	import libraries with those DATA exports. Note:	Use of
	   the 'auto-import' extension will cause the text section of the  im-
	   age	file to	be made	writable. This does not	conform	to the PE-COFF
	   format specification	published by Microsoft.

	   Using 'auto-import' generally will 'just work' -- but sometimes you
	   may see this	message:

	   "variable  '<var>' can't be auto-imported. Please read the documen-
	   tation for ld's "--enable-auto-import" for details."

	   This	message	occurs when some (sub)expression accesses  an  address
	   ultimately  given  by the sum of two	constants (Win32 import	tables
	   only	allow one).  Instances where this may occur  include  accesses
	   to  member  fields of struct	variables imported from	a DLL, as well
	   as using a constant index into an array variable  imported  from  a
	   DLL.	  Any multiword	variable (arrays, structs, long	long, etc) may
	   trigger this	error condition.  However,  regardless	of  the	 exact
	   data	type of	the offending exported variable, ld will always	detect
	   it, issue the warning, and exit.

	   There are several ways to address this  difficulty,	regardless  of
	   the data type of the	exported variable:

	   One way is to use --enable-runtime-pseudo-reloc switch. This	leaves
	   the task of adjusting references in your client  code  for  runtime
	   environment,	 so  this  method  works only when runtime environment
	   supports this feature.

	   A second solution is	to force one of	the 'constants'	to be a	 vari-
	   able	 --  that is, unknown and un-optimizable at compile time.  For
	   arrays, there are two possibilities:	a) make	the indexee  (the  ar-
	   ray's  address) a variable, or b) make the 'constant' index a vari-
	   able.  Thus:

		   extern type extern_array[];
		   extern_array[1] -->
		      {	volatile type *t=extern_array; t[1] }

	   or

		   extern type extern_array[];
		   extern_array[1] -->
		      {	volatile int t=1; extern_array[t] }

	   For structs (and most other multiword data types) the  only	option
	   is  to  make	the struct itself (or the long long, or	the ...) vari-
	   able:

		   extern struct s extern_struct;
		   extern_struct.field -->
		      {	volatile struct	s *t=&extern_struct; t->field }

	   or

		   extern long long extern_ll;
		   extern_ll -->
		     { volatile	long long * local_ll=&extern_ll; *local_ll }

	   A third method of  dealing  with  this  difficulty  is  to  abandon
	   'auto-import'  for  the  offending  symbol  and mark	it with	"__de-
	   clspec(dllimport)".	However, in practise that requires using  com-
	   pile-time  #defines	to  indicate  whether  you are building	a DLL,
	   building client code	that will link to the DLL,  or	merely	build-
	   ing/linking to a static library.   In making	the choice between the
	   various methods of resolving	the 'direct address with constant off-
	   set'	problem, you should consider typical real-world	usage:

	   Original:

		   --foo.h
		   extern int arr[];
		   --foo.c
		   #include "foo.h"
		   void	main(int argc, char **argv){
		     printf("%d\n",arr[1]);
		   }

	   Solution 1:

		   --foo.h
		   extern int arr[];
		   --foo.c
		   #include "foo.h"
		   void	main(int argc, char **argv){
		     /*	This workaround	is for win32 and cygwin; do not	"optimize" */
		     volatile int *parr	= arr;
		     printf("%d\n",parr[1]);
		   }

	   Solution 2:

		   --foo.h
		   /* Note: auto-export	is assumed (no __declspec(dllexport)) */
		   #if (defined(_WIN32)	|| defined(__CYGWIN__))	&& \
		     !(defined(FOO_BUILD_DLL) || defined(FOO_STATIC))
		   #define FOO_IMPORT __declspec(dllimport)
		   #else
		   #define FOO_IMPORT
		   #endif
		   extern FOO_IMPORT int arr[];
		   --foo.c
		   #include "foo.h"
		   void	main(int argc, char **argv){
		     printf("%d\n",arr[1]);
		   }

	   A  fourth  way  to avoid this problem is to re-code your library to
	   use a functional interface rather than a data interface for the of-
	   fending  variables  (e.g.  set_foo()	 and  get_foo()	accessor func-
	   tions).  [This option is specific to	the i386 PE targeted  port  of
	   the linker]

       --disable-auto-import
	   Do  not  attempt  to	 do  sophisticated  linking  of	 "_symbol"  to
	   "__imp__symbol" for DATA imports from DLLs.	[This option  is  spe-
	   cific to the	i386 PE	targeted port of the linker]

       --enable-runtime-pseudo-reloc
	   If your code	contains expressions described in --enable-auto-import
	   section, that is, DATA imports from DLL with	non-zero offset,  this
	   switch  will	 create	a vector of 'runtime pseudo relocations' which
	   can be used by runtime environment to  adjust  references  to  such
	   data	 in your client	code.  [This option is specific	to the i386 PE
	   targeted port of the	linker]

       --disable-runtime-pseudo-reloc
	   Do not create pseudo	relocations for	non-zero offset	 DATA  imports
	   from	 DLLs.	 This is the default.  [This option is specific	to the
	   i386	PE targeted port of the	linker]

       --enable-extra-pe-debug
	   Show	additional debug info related to auto-import symbol  thunking.
	   [This  option  is  specific	to  the	 i386  PE targeted port	of the
	   linker]

       --section-alignment
	   Sets	the section alignment.	Sections in memory will	 always	 begin
	   at  addresses  which	 are  a	 multiple of this number.  Defaults to
	   0x1000.  [This option is specific to	the i386 PE targeted  port  of
	   the linker]

       --stack reserve
       --stack reserve,commit
	   Specify  the	amount of memory to reserve (and optionally commit) to
	   be used as stack for	this program.  The default is 2Mb reserved, 4K
	   committed.	[This  option is specific to the i386 PE targeted port
	   of the linker]

       --subsystem which
       --subsystem which:major
       --subsystem which:major.minor
	   Specifies the subsystem under which your program will execute.  The
	   legal  values  for  which  are  "native", "windows",	"console", and
	   "posix".  You may optionally	set the	subsystem version also.	 [This
	   option is specific to the i386 PE targeted port of the linker]

ENVIRONMENT
       You can change the behaviour of ld with the environment variables "GNU-
       TARGET",	"LDEMULATION" and "COLLECT_NO_DEMANGLE".

       "GNUTARGET" determines the input-file object format if you don't	use -b
       (or  its	 synonym  --format).  Its value	should be one of the BFD names
       for an input format.  If	there is no "GNUTARGET"	in the environment, ld
       uses  the  natural  format of the target. If "GNUTARGET"	is set to "de-
       fault" then BFD attempts	to discover the	input format by	examining  bi-
       nary  input  files; this	method often succeeds, but there are potential
       ambiguities, since there	is no method of	ensuring that the magic	number
       used to specify object-file formats is unique.  However,	the configura-
       tion procedure for BFD on each system places  the  conventional	format
       for  that  system first in the search-list, so ambiguities are resolved
       in favor	of convention.

       "LDEMULATION" determines	the default emulation if you don't use the  -m
       option.	 The emulation can affect various aspects of linker behaviour,
       particularly the	default	linker script.	You can	list the available em-
       ulations	 with  the  --verbose  or -V options.  If the -m option	is not
       used, and the "LDEMULATION" environment variable	is  not	 defined,  the
       default emulation depends upon how the linker was configured.

       Normally,  the  linker will default to demangling symbols.  However, if
       "COLLECT_NO_DEMANGLE" is	set in the environment,	then it	 will  default
       to not demangling symbols.  This	environment variable is	used in	a sim-
       ilar fashion by the "gcc" linker	wrapper	program.  The default  may  be
       overridden by the --demangle and	--no-demangle options.

SEE ALSO
       ar(1),  nm(1),  objcopy(1), objdump(1), readelf(1) and the Info entries
       for binutils and	ld.

COPYRIGHT
       Copyright (c) 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000,  2001,	 2002,
       2003, 2004 Free Software	Foundation, Inc.

       Permission  is  granted to copy,	distribute and/or modify this document
       under the terms of the GNU Free Documentation License, Version  1.1  or
       any  later  version  published by the Free Software Foundation; with no
       Invariant Sections, with	no Front-Cover Texts, and with	no  Back-Cover
       Texts.  A copy of the license is	included in the	section	entitled ``GNU
       Free Documentation License''.

binutils-2.15			  2004-05-17				 LD(1)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | ENVIRONMENT | SEE ALSO | COPYRIGHT

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