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LD(1)                        GNU Development Tools                       LD(1)



NAME
       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 total control over the
       linking process.

       This man page does not describe the command language; see the ld entry in "info"
       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 execution 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 standard, 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 options.  Repeating non-file options with a
       different argument will either have no further effect, or override prior
       occurrences (those further to the left on the command line) of that option.
       Options which may be meaningfully specified more than once are noted in the
       descriptions below.

       Non-option arguments are object files or archives which are to be linked together.
       They may follow, precede, or be mixed in with command-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 specified, 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 augments 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
       "INPUT" or "GROUP" to load other objects.  Specifying a script in this way merely
       augments the main linker script, with the extra commands placed after the main
       script; use the -T option to replace the default linker script entirely, but note
       the effect of the "INSERT" command.

       For options whose names are a single letter, option arguments must either follow
       the option letter without intervening whitespace, or be given as separate arguments
       immediately following the option that requires 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 preceded 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 immediately following the
       option that requires them.  For example, --trace-symbol foo and --trace-symbol=foo
       are equivalent.  Unique abbreviations 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,--start-group foo.o bar.o -Wl,--end-group

       This is important, because otherwise the compiler driver program may silently drop
       the linker options, resulting in a bad link.  Confusion may also arise when passing
       options that require values through a driver, as the use of a space between option
       and argument acts as a separator, and causes the driver to pass only the option to
       the linker and the argument to the compiler.  In this case, it is simplest to use
       the joined forms of both single- and multiple-letter options, such as:

                 gcc foo.o bar.o -Wl,-eENTRY -Wl,-Map=a.map

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

       @file
           Read command-line options from file.  The options read are inserted in place of
           the original @file option.  If file does not exist, or cannot be read, then the
           option will be treated literally, and not removed.

           Options in file are separated by whitespace.  A whitespace character may be
           included in an option by surrounding the entire option in either single or
           double quotes.  Any character (including a backslash) may be included by
           prefixing the character to be included with a backslash.  The file may itself
           contain additional @file options; any such options will be processed
           recursively.

       -a keyword
           This option is supported for HP/UX compatibility.  The keyword argument 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.

       --audit AUDITLIB
           Adds AUDITLIB to the "DT_AUDIT" entry of the dynamic section.  AUDITLIB is not
           checked for existence, nor will it use the DT_SONAME specified in the library.
           If specified multiple times "DT_AUDIT" will contain a colon separated list of
           audit interfaces to use. If the linker finds an object with an audit entry
           while searching for shared libraries, it will add a corresponding "DT_DEPAUDIT"
           entry in the output file.  This option is only meaningful on ELF platforms
           supporting the rtld-audit interface.

       -A architecture
       --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-library 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 explicitly (when linking object
           files of different formats), by including -b input-format before each group of
           object files in a particular format.

           The default format is taken from the environment variable "GNUTARGET".

           You can also define the input format from a script, using the command "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, described in the MRI Compatible
           Script Files section of GNU ld documentation.  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.

       --depaudit AUDITLIB
       -P AUDITLIB
           Adds AUDITLIB to the "DT_DEPAUDIT" entry of the dynamic section.  AUDITLIB is
           not checked for existence, nor will it use the DT_SONAME specified in the
           library.  If specified multiple times "DT_DEPAUDIT" will contain a colon
           separated list of audit interfaces to use.  This option is only meaningful on
           ELF platforms supporting the rtld-audit interface.  The -P option is provided
           for Solaris compatibility.

       -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 symbol 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).

       --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.  This option is available only for the i386 PE
           targeted port of the linker and for ELF targeted ports.  For i386 PE, symbols
           explicitly listed in a .def file are still exported, regardless of this option.
           For ELF targeted ports, symbols affected by this option will be treated as
           hidden.

       --exclude-modules-for-implib module,module,...
           Specifies a list of object files or archive members, from which symbols should
           not be automatically exported, but which should be copied wholesale into the
           import library being generated during the link.  The module names may be
           delimited by commas or colons, and must match exactly the filenames used by ld
           to open the files; for archive members, this is simply the member name, but for
           object files the name listed must include and match precisely any path used to
           specify the input file on the linker's command-line.  This option is available
           only for the i386 PE targeted port of the linker.  Symbols explicitly listed in
           a .def file are still exported, regardless of this option.

       -E
       --export-dynamic
       --no-export-dynamic
           When creating a dynamically linked executable, using the -E option or the
           --export-dynamic option causes the linker to 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 either of these options (or use the --no-export-dynamic
           option to restore the default behavior), the dynamic symbol table will normally
           contain only those symbols which are referenced by some dynamic 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 dynamic list to control what symbols should be added to
           the dynamic symbol table if the output format supports it.  See the description
           of --dynamic-list.

           Note that this option is specific to ELF targeted ports.  PE targets support a
           similar function to export all symbols from a DLL or EXE; see the description
           of --export-all-symbols below.

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

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

       -f name
       --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 auxiliary 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 debugging or for
           machine specific performance.

           This option may be specified more than once.  The DT_AUXILIARY entries will be
           created in the order in which they appear on the command 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
           provided by the object name.

           Some older linkers used the -F option throughout a compilation toolchain for
           specifying object-file format for both input and output 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.

       -G value
       --gpsize=value
           Set the maximum size of objects to be optimized using the GP register 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.

       -h name
       -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.

       -l namespec
       --library=namespec
           Add the archive or object file specified by namespec to the list of files to
           link.  This option may be used any number of times.  If namespec is of the form
           :filename, ld will search the library path for a file called filename,
           otherwise it will search the library path for a file called libnamespec.a.

           On systems which support shared libraries, ld may also search for files other
           than libnamespec.a.  Specifically, on ELF and SunOS systems, ld will search a
           directory for a library called libnamespec.so before searching for one called
           libnamespec.a.  (By convention, a ".so" extension indicates a shared library.)
           Note that this behavior does not apply to :filename, which always specifies a
           file called filename.

           The linker will search an archive only once, at the location where it is
           specified on the command line.  If the archive defines a symbol which was
           undefined in some object which appeared before the archive on the command line,
           the linker will include the appropriate 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.  However, if you
           are using ld on AIX, note that it is different from the behaviour of the AIX
           linker.

       -L searchdir
       --library-path=searchdir
           Add path searchdir to the list of paths that ld will search for archive
           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 specified on the command line are searched before
           the default directories.  All -L options apply to all -l options, regardless of
           the order in which the options appear.  -L options do not affect how ld
           searches for a linker script unless -T option is specified.

           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.

       -m emulation
           Emulate the emulation linker.  You can list the available emulations 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 information about
           the link, including the following:

           ?   Where object files 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.

           ?   The values assigned to symbols.

               Note - symbols whose values are computed by an expression which involves a
               reference to a previous value of the same symbol may not have correct
               result displayed in the link map.  This is because the linker discards
               intermediate results and only retains the final value of an expression.
               Under such circumstances the linker will display the final value enclosed
               by square brackets.  Thus for example a linker script containing:

                          foo = 1
                          foo = foo * 4
                          foo = foo + 8

               will produce the following output in the link map if the -M option is used:

                          0x00000001                foo = 0x1
                          [0x0000000c]                foo = (foo * 0x4)
                          [0x0000000c]                foo = (foo + 0x8)

               See Expressions for more information about expressions in linker scripts.

       -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 option 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 probably should only be enabled
           for the final binary.  At the moment this option only affects ELF shared
           library generation.  Future releases of the linker may make more use of this
           option.  Also currently there is no difference in the linker's behaviour for
           different non-zero values of this option.  Again this may change with future
           releases.

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

           This option is currently only supported on ELF platforms.

       --force-dynamic
           Force the output file to have dynamic sections.  This option is specific to
           VxWorks targets.

       -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 relocate 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 followed 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 default 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.  Multiple -T options accumulate.

       -dT scriptfile
       --default-script=scriptfile
           Use scriptfile as the default linker script.

           This option is similar to the --script option except that processing of the
           script is delayed until after the rest of the command line has been processed.
           This allows options placed after the --default-script option on the command
           line to affect the behaviour of the linker script, which can be important when
           the linker command line cannot be directly controlled by the user.  (eg because
           the command line is being constructed by another tool, such as gcc).

       -u symbol
       --undefined=symbol
           Force symbol to be entered in the output file as an undefined symbol.  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 option 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 assignments 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.  (These symbols start with system-specific
           local label prefixes, typically .L for ELF systems or L for traditional a.out
           systems.)

       -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.

           execstack
               Marks the object as requiring executable stack.

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

           lazy
               When generating an executable or shared library, mark it to tell the
               dynamic linker to defer function call resolution to the point when the
               function is called (lazy binding), rather than at load time.  Lazy binding
               is the default.

           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 object 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".

           noexecstack
               Marks the object as not requiring executable stack.

           norelro
               Don't create an ELF "PT_GNU_RELRO" segment header in the object.

           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.

           relro
               Create an ELF "PT_GNU_RELRO" segment header in the object.

           max-page-size=value
               Set the emulation maximum page size to value.

           common-page-size=value
               Set the emulation common page size to value.

           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 undefined
           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 symbol referred to by an object in an archive
           that appears later on the command line, the linker would not be able to resolve
           that reference.  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 between 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 mentioned on the
           command line after the --as-needed option.  Normally the linker will add a
           DT_NEEDED tag for each dynamic library mentioned on the command line,
           regardless of whether the library is actually needed or not.  --as-needed
           causes a DT_NEEDED tag to only be emitted for a library that satisfies an
           undefined symbol reference from a regular object file or, if the library is not
           found in the DT_NEEDED lists of other libraries linked up to that point, an
           undefined symbol reference from another dynamic library.  --no-as-needed
           restores the default behaviour.

       --add-needed
       --no-add-needed
           These two options have been deprecated because of the similarity of their names
           to the --as-needed and --no-as-needed options.  They have been replaced by
           --copy-dt-needed-entries and --no-copy-dt-needed-entries.

       -assert keyword
           This option is ignored for SunOS compatibility.

       -Bdynamic
       -dy
       -call_shared
           Link against dynamic libraries.  This is only meaningful on platforms 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 library 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 affects library searching for -l options which
           follow it.  This option also implies --unresolved-symbols=report-all.  This
           option can be used with -shared.  Doing so means that a shared library is being
           created but that all of the library's external references must be resolved by
           pulling in entries from static libraries.

       -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 override the definition within the
           shared library.  This option is only meaningful on ELF platforms which support
           shared libraries.

       -Bsymbolic-functions
           When creating a shared library, bind references to global function symbols to
           the definition within the shared library, if any.  This option is only
           meaningful on ELF platforms which support shared libraries.

       --dynamic-list=dynamic-list-file
           Specify the name of a dynamic list file to the linker.  This is typically used
           when creating shared libraries to specify a list of global symbols whose
           references shouldn't be bound to the definition within the shared library, or
           creating dynamically linked executables to specify a list of symbols which
           should be added to the symbol table in the executable.  This option is only
           meaningful on ELF platforms which support shared libraries.

           The format of the dynamic list is the same as the version node without scope
           and node name.  See VERSION for more information.

       --dynamic-list-data
           Include all global data symbols to the dynamic list.

       --dynamic-list-cpp-new
           Provide the builtin dynamic list for C++ operator new and delete.  It is mainly
           useful for building shared libstdc++.

       --dynamic-list-cpp-typeinfo
           Provide the builtin dynamic list for C++ runtime type identification.

       --check-sections
       --no-check-sections
           Asks the linker not to check section addresses after they have been assigned to
           see if there are 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.  Section overlap is not usually checked for relocatable
           links.  You can force checking in that case by using the --check-sections
           option.

       --copy-dt-needed-entries
       --no-copy-dt-needed-entries
           This option affects the treatment of dynamic libraries referred to by DT_NEEDED
           tags inside ELF dynamic libraries mentioned on the command line.  Normally the
           linker will add a DT_NEEDED tag to the output binary for each library mentioned
           in a DT_NEEDED tag in an input dynamic library.  With
           --no-copy-dt-needed-entries specified on the command line however any dynamic
           libraries that follow it will have their DT_NEEDED entries ignored.  The
           default behaviour can be restored with --copy-dt-needed-entries.

           This option also has an effect on the resolution of symbols in dynamic
           libraries.  With the default setting dynamic libraries mentioned on the command
           line will be recursively searched, following their DT_NEEDED tags to other
           libraries, in order to resolve symbols required by the output binary.  With
           --no-copy-dt-needed-entries specified however the searching of dynamic
           libraries that follow it will stop with the dynamic library itself.  No
           DT_NEEDED links will be traversed to resolve symbols.

       --cref
           Output a cross reference table.  If a linker map file is being generated, the
           cross reference table is printed to the map file.  Otherwise, 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 location 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 assign
           addresses to Common symbols from the choice of the output file type; otherwise
           a non-Relocatable output type forces assigning addresses 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 duplicate 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 existing symbol, or use "+" and "-" to add or
           subtract hexadecimal constants or symbols.  If you need more elaborate
           expressions, consider 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.  Different compilers have different mangling styles.  The
           optional demangling style argument can be used to choose an appropriate
           demangling 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.

       -Ifile
       --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.

       --fatal-warnings
       --no-fatal-warnings
           Treat all warnings as errors.  The default behaviour can be restored with the
           option --no-fatal-warnings.

       --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 option is useful when using unmodified
           Unix makefiles on a Microsoft Windows host, since some versions of Windows
           won't run an image unless it ends in a ".exe" suffix.

       --gc-sections
       --no-gc-sections
           Enable garbage collection of unused input sections.  It is ignored on targets
           that do not support this option.  The default behaviour (of not performing this
           garbage collection) can be restored by specifying --no-gc-sections on the
           command line.

           --gc-sections decides which input sections are used by examining symbols and
           relocations.  The section containing the entry symbol and all sections
           containing symbols undefined on the command-line will be kept, as will sections
           containing symbols referenced by dynamic objects.  Note that when building
           shared libraries, the linker must assume that any visible symbol is referenced.
           Once this initial set of sections has been determined, the linker recursively
           marks as used any section referenced by their relocations.  See --entry and
           --undefined.

           This option can be set when doing a partial link (enabled with option -r).  In
           this case the root of symbols kept must be explicitely specified either by an
           --entry or --undefined option or by a "ENTRY" command in the linker script.

       --print-gc-sections
       --no-print-gc-sections
           List all sections removed by garbage collection.  The listing is printed on
           stderr.  This option is only effective if garbage collection has been enabled
           via the --gc-sections) option.  The default behaviour (of not listing the
           sections that are removed) can be restored by specifying --no-print-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 output 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 behaviour for reporting unresolved
           references found in shared libraries 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 or disallows undefined symbols in shared libraries.  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 default behaviour is to report errors for any undefined symbols referenced
           in shared libraries if the linker is being used to create an executable, but to
           allow them if the linker is being used to create a shared library.

           The reasons for allowing undefined symbol references in shared libraries
           specified at link time are that:

           ?   A shared library specified at link time may not be the same as the one that
               is available at load time, so the symbol might actually be resolvable at
               load time.

           ?   There are some operating systems, eg BeOS and HPPA, where undefined symbols
               in shared libraries are normal.

               The BeOS kernel for example patches shared libraries at load time to select
               whichever function is most appropriate for the current architecture.  This
               is used, for example, to dynamically select an appropriate memset function.

       --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.

       --default-symver
           Create and use a default symbol version (the soname) for unversioned exported
           symbols.

       --default-imported-symver
           Create and use a default symbol version (the soname) for unversioned imported
           symbols.

       --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 endiannesses.  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-warn-search-mismatch
           Normally ld will give a warning if it finds an incompatible library during a
           library search.  This option silences the warning.

       --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 encounters 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 dynamic linker to the virtual
           address the OS chooses for them (which can vary between invocations).  Like
           normal dynamically linked executables 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 supported 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 instructions 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 gradually, to conserve run-time memory.

           --retain-symbols-file does not discard undefined symbols, or symbols 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 arguments 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 options 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 file systems.

           For compatibility with other ELF linkers, if the -R option is followed 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 locate 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 specifying 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 runtime, whereas the -rpath-link
               option is only effective at link time. Searching -rpath in this way is only
               supported by native linkers and cross linkers which have been configured
               with the --with-sysroot option.

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

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

           5.  For a native linker, the search 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 libraries 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
       --sort-common=ascending
       --sort-common=descending
           This option tells ld to sort the common symbols by alignment in ascending or
           descending order when it places them in the appropriate output sections.  The
           symbol alignments considered are sixteen-byte or larger, eight-byte, four-byte,
           two-byte, and one-byte. This is to prevent gaps between symbols due to
           alignment constraints.  If no sorting order is specified, then descending order
           is assumed.

       --sort-section=name
           This option will apply "SORT_BY_NAME" to all wildcard section patterns in the
           linker script.

       --sort-section=alignment
           This option will apply "SORT_BY_ALIGNMENT" to all wildcard section patterns in
           the linker script.

       --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 single output
           section in the file contains more than count relocations.  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 relocations 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 redistribution, so if a single input
           section contains more than count relocations 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.

       --sysroot=directory
           Use directory as the location of the sysroot, overriding the configure-time
           default.  This option is only supported by linkers that were configured using
           --with-sysroot.

       --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 locate 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.

       -Ttext-segment=org
           When creating an ELF executable or shared object, it will set the address of
           the first byte of the text segment.

       --unresolved-symbols=method
           Determine how to handle unresolved symbols.  There are four possible 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 libraries, 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 included on the linker's command line.

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

           Normally the linker will generate an error message for each reported 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 typically used
           when creating shared libraries to specify additional information about the
           version hierarchy for the library being created.  This option is only fully
           supported on ELF platforms which support shared libraries; see VERSION.  It is
           partially supported on PE platforms, which can use version scripts to filter
           symbol visibility in auto-export mode: any symbols marked local in the version
           script will not be exported.

       --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 examples:

           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 symbols 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 different sizes, it picks the largest size.  The
               linker turns a common 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 encountered 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 already 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 definition 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 symbol.

                       <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 multiple global pointer
           values in order to be able to address all possible 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 module 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 section.  The address will
           only be changed if it not explicitly specified; that is, if the "SECTIONS"
           command does not specify a start address for the section.

       --warn-shared-textrel
           Warn if the linker adds a DT_TEXTREL to a shared object.

       --warn-alternate-em
           Warn if an object has alternate ELF machine code.

       --warn-unresolved-symbols
           If the linker is going to report an unresolved symbol (see the option
           --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 archives, 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 symbol 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".

       --eh-frame-hdr
           Request creation of ".eh_frame_hdr" section and ELF "PT_GNU_EH_FRAME" segment
           header.

       --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 --enable-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.

       --hash-size=number
           Set the default size of the linker's hash tables to a prime number close to
           number.  Increasing this value can reduce the length of time it takes the
           linker to perform its tasks, at the expense of increasing the linker's memory
           requirements.  Similarly reducing this value can reduce the memory requirements
           at the expense of speed.

       --hash-style=style
           Set the type of linker's hash table(s).  style can be either "sysv" for classic
           ELF ".hash" section, "gnu" for new style GNU ".gnu.hash" section or "both" for
           both the classic ELF ".hash" and new style GNU ".gnu.hash" hash tables.  The
           default is "sysv".

       --reduce-memory-overheads
           This option reduces memory requirements at ld runtime, at the expense of
           linking speed.  This was introduced to select the old O(n^2) algorithm for link
           map file generation, rather than the new O(n) algorithm which uses about 40%
           more memory for symbol storage.

           Another effect of the switch is to set the default hash table size to 1021,
           which again saves memory at the cost of lengthening the linker's run time.
           This is not done however if the --hash-size switch has been used.

           The --reduce-memory-overheads switch may be also be used to enable other
           tradeoffs in future versions of the linker.

       --build-id
       --build-id=style
           Request creation of ".note.gnu.build-id" ELF note section.  The contents of the
           note are unique bits identifying this linked file.  style can be "uuid" to use
           128 random bits, "sha1" to use a 160-bit SHA1 hash on the normative parts of
           the output contents, "md5" to use a 128-bit MD5 hash on the normative parts of
           the output contents, or "0xhexstring" to use a chosen bit string specified as
           an even number of hexadecimal digits ("-" and ":" characters between digit
           pairs are ignored).  If style is omitted, "sha1" is used.

           The "md5" and "sha1" styles produces an identifier that is always the same in
           an identical output file, but will be unique among all nonidentical output
           files.  It is not intended to be compared as a checksum for the file's
           contents.  A linked file may be changed later by other tools, but the build ID
           bit string identifying the original linked file does not change.

           Passing "none" for style disables the setting from any "--build-id" options
           earlier on the command line.

       The i386 PE linker supports the -shared option, which causes the output to be a
       dynamically linked library (DLL) instead of a normal executable.  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 option is specific to the
           i386 PE targeted port of the linker]

       --enable-long-section-names
       --disable-long-section-names
           The PE variants of the Coff object format add an extension that permits the use
           of section names longer than eight characters, the normal limit for Coff.  By
           default, these names are only allowed in object files, as fully-linked
           executable images do not carry the Coff string table required to support the
           longer names.  As a GNU extension, it is possible to allow their use in
           executable images as well, or to (probably pointlessly!)  disallow it in object
           files, by using these two options.  Executable images generated with these long
           section names are slightly non-standard, carrying as they do a string table,
           and may generate confusing output when examined with non-GNU PE-aware tools,
           such as file viewers and dumpers.  However, GDB relies on the use of PE long
           section names to find Dwarf-2 debug information sections in an executable image
           at runtime, and so if neither option is specified on the command-line, ld will
           enable long section names, overriding the default and technically correct
           behaviour, when it finds the presence of debug information while linking an
           executable image and not stripping symbols.  [This option is valid for all PE
           targeted ports 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 --disable-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 function attributes, the default is to not export
           anything else unless this option is given.  Note that the symbols "DllMain@12",
           "DllEntryPoint@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 internal layout such as those
           beginning with "_head_" or ending with "_iname".  In addition, no symbols from
           "libgcc", "libstd++", "libmingw32", 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_noncygwin_dll_entry@12", "_fmode",
           "_impure_ptr", "cygwin_attach_dll", "cygwin_premain0", "cygwin_premain1",
           "cygwin_premain2", "cygwin_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 exported.  The
           symbol names may be delimited by commas or colons.  [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 number of bytes 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 overlap any other dlls.  The default is
           0x400000 for executables, and 0x10000000 for dlls.  [This option is specific to
           the i386 PE targeted 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]

       --large-address-aware
           If given, the appropriate bit in the "Characteristics" field of the COFF header
           is set to indicate that this executable supports virtual addresses greater than
           2 gigabytes.  This should be used in conjunction with the /3GB or /USERVA=value
           megabytes switch in the "[operating systems]" section of the BOOT.INI.
           Otherwise, this bit has no effect.  [This option is specific to PE targeted
           ports 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 automatically 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 specified using the
           "--image-base" argument.  By using a hash generated from the dllname to create
           unique image bases for each DLL, in-memory 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 instance, 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 image file to be made writable. This does
           not conform to the PE-COFF format specification published by Microsoft.

           Note - use of the 'auto-import' extension will also cause read only data which
           would normally be placed into the .rdata section to be placed into the .data
           section instead.  This is in order to work around a problem with consts that is
           described here: http://www.cygwin.com/ml/cygwin/2004-09/msg01101.html

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

           "variable '<var>' can't be auto-imported. Please read the documentation 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 variable -- that
           is, unknown and un-optimizable at compile time.  For arrays, there are two
           possibilities: a) make the indexee (the array's address) a variable, or b) make
           the 'constant' index a variable.  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 ...) variable:

                   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 "__declspec(dllimport)".  However, in
           practise that requires using compile-time #defines to indicate whether you are
           building a DLL, building client code that will link to the DLL, or merely
           building/linking to a static library.   In making the choice between the
           various methods of resolving the 'direct address with constant offset' 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 offending variables
           (e.g. set_foo() and get_foo() accessor functions).  [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 specific 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 number of bytes 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", "posix", and "xbox".  You
           may optionally set the subsystem version also.  Numeric values are also
           accepted for which.  [This option is specific to the i386 PE targeted port of
           the linker]

           The following options set flags in the "DllCharacteristics" field of the PE
           file header: [These options are specific to PE targeted ports of the linker]

       --dynamicbase
           The image base address may be relocated using address space layout
           randomization (ASLR).  This feature was introduced with MS Windows Vista for
           i386 PE targets.

       --forceinteg
           Code integrity checks are enforced.

       --nxcompat
           The image is compatible with the Data Execution Prevention.  This feature was
           introduced with MS Windows XP SP2 for i386 PE targets.

       --no-isolation
           Although the image understands isolation, do not isolate the image.

       --no-seh
           The image does not use SEH. No SE handler may be called from this image.

       --no-bind
           Do not bind this image.

       --wdmdriver
           The driver uses the MS Windows Driver Model.

       --tsaware
           The image is Terminal Server aware.

       The 68HC11 and 68HC12 linkers support specific options to control the memory bank
       switching mapping and trampoline code generation.

       --no-trampoline
           This option disables the generation of trampoline. By default a trampoline is
           generated for each far function which is called using a "jsr" instruction (this
           happens when a pointer to a far function is taken).

       --bank-window name
           This option indicates to the linker the name of the memory region in the MEMORY
           specification that describes the memory bank window.  The definition of such
           region is then used by the linker to compute paging and addresses within the
           memory window.

       The following options are supported to control handling of GOT generation when
       linking for 68K targets.

       --got=type
           This option tells the linker which GOT generation scheme to use.  type should
           be one of single, negative, multigot or target.  For more information refer to
           the Info entry for ld.

ENVIRONMENT
       You can change the behaviour of ld with the environment variables "GNUTARGET",
       "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 "default" then BFD attempts to discover the input
       format by examining binary 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 configuration
       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 emulations 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 similar 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,
       2005, 2006, 2007, 2008, 2009 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 1.3 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".



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