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LD(1)                        GNU Development Tools                       LD(1)

NAME
       ld - Using LD, the GNU linker

SYNOPSIS
       ld [options] objfile ...

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

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

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

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

       Aside from its flexibility, the GNU linker is more helpful than other
       linkers in providing diagnostic information.  Many linkers abandon
       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.  Note that specifying a
       script in this way merely augments the main linker script; use the -T
       option to replace the default linker script entirely.

       For options whose names are a single letter, option arguments must
       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 preceeded by two dashes.  This is to reduce confusion with the
       -o option.  So for example -omagic sets the output file name to magic
       whereas --omagic sets the NMAGIC flag on the output.

       Arguments to multiple-letter options must either be separated from the
       option name by an equals sign, or be given as separate arguments
       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,--startgroup foo.o bar.o -Wl,--endgroup

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

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

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

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

       -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).

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

           If you do not use this option, the dynamic symbol table will
           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 version script to control what symbols should
           be added to the dynamic symbol table if the output format supports
           it.  See the description of --version-script in @ref{VERSION}.

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

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

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

       -Gvalue
       --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.

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

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

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

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

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

           The linker will search an archive only once, at the location where
           it is specified on the command line.  If the archive defines a
           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.

       -Lsearchdir
       --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.

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

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

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

       -memulation
           Emulate the emulation linker.  You can list the available
           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 and symbols are mapped into memory.

           *   How common symbols are allocated.

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

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

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

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

       -o output
       --output=output
           Use output as the name for the program produced by ld; if this
           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.

       -q
       --emit-relocs
           Leave relocation sections and contents in fully linked
           exececutables.  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.

       -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.

       -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.  For most targets, this is all
           local symbols whose names begin with L.

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

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

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

       -z keyword
           The recognized keywords are:

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

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

           initfirst
               This option is only meaningful when building a shared object.
               It marks the object so that its runtime initialization will
               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.

           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".

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

           origin
               Marks the object may contain $ORIGIN.

           Other keywords are ignored for Solaris compatibility.

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

           The specified archives are searched repeatedly until no new
           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. --as-needed causes DT_NEEDED tags to
           only be emitted for libraries that satisfy some reference from
           regular objects.  --no-as-needed restores the default behaviour.

       -assert keyword
           This option is ignored for SunOS compatibility.

       -Bdynamic
       -dy
       -call_shared
           Link against dynamic libraries.  This is only meaningful on
           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.

       -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.

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

       --cref
           Output a cross reference table.  If a linker map file is being
           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.

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

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

       --fatal-warnings
           Treat all warnings as errors.

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

           If a successfully built fully linked output file does not have a
           ".exe" or ".dll" suffix, this option forces the linker to copy the
           output file to one of the same name with a ".exe" suffix. This
           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.

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

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

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

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

       --no-warn-mismatch
           Normally ld will give an error if you try to link together input
           files that are mismatched for some reason, perhaps because they
           have been compiled for different processors or for different
           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-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 filesystems.

           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. It is for the native linker only.

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

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

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

           6.  For a native ELF linker, the directories in "DT_RUNPATH" or
               "DT_RPATH" of a shared library are searched for shared
               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
           This option tells ld to sort the common symbols by size when it
           places them in the appropriate output sections.  First come all the
           one byte symbols, then all the two byte, then all the four byte,
           and then everything else.  This is to prevent gaps between symbols
           due to alignment constraints.

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

       --split-by-reloc [count]
           Tries to creates extra sections in the output file so that no
           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.

       --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.

       --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 meaningful on ELF platforms which
           support shared libraries.

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

           There are three kinds of global symbols, illustrated here by C
           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-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".

       --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.

       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-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]

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

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

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

       --image-base value
           Use value as the base address of your program or dll.  This is the
           lowest memory location that will be used when your program or dll
           is loaded.  To reduce the need to relocate and improve performance
           of your dlls, each should have a unique base address and not
           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]

       --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.

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

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

ENVIRONMENT
       You can change the behaviour of ld with the environment variables
       "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 Free Software Foundation, Inc.

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

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

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

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