sh-rtems-ld






ld − Using LD, the GNU linker

ld [options] objfile ...

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.

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









                             ‐2‐


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 can not 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.











                             ‐3‐


     Note − if the linker is being invoked indirectly, via a
compiler driver (eg 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









                             ‐4‐


    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.










                             ‐5‐


    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









                             ‐6‐


    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.











                             ‐7‐


−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.

    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









                             ‐8‐


    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.  If
    the output format supports Unix style magic numbers,
    mark the output as "OMAGIC".

−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









                             ‐9‐


    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

−−relocateable
    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











                            ‐10‐


−−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









                            ‐11‐


    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 "initfirst", "interpose",
    "loadfltr", "nodefaultlib", "nodelete", "nodlopen",
    "nodump", "now", "origin", "combreloc", "nocombreloc"
    and "nocopyreloc".  The other keywords are ignored for
    Solaris compatibility. "initfirst" marks the object to
    be initialized first at runtime before 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 filtees
    be processed immediately at runtime.  "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" marks the object with
    the non‐lazy runtime binding.  "origin" marks the object









                            ‐12‐


    may contain $ORIGIN.  "defs" disallows undefined
    symbols.  "muldefs" allows multiple definitions.
    "combreloc" combines multiple reloc sections and sorts
    them to make dynamic symbol lookup caching possible.
    "nocombreloc" disables multiple reloc sections
    combining.  "nocopyreloc" disables production of copy
    relocs.

−( 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.

−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.  −−no−undefined is
    implied.  This option is only meaningful on ELF
    platforms which support shared libraries.











                            ‐13‐


−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.

−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.









                            ‐14‐


    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









                            ‐15‐


    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
    Normally when creating a non‐symbolic shared library,
    undefined symbols are allowed and left to be resolved by









                            ‐16‐


    the runtime loader.  These options disallows such
    undefined symbols.

−−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
    Allow undefined symbols in shared objects even  when
    −−no−undefined is set. The net result will be that
    undefined symbols in regular objects will still trigger
    an error, but undefined symbols in shared objects will
    be ignored.  The implementation of no_undefined makes
    the assumption that the runtime linker will choke on
    undefined symbols.  However there is at least one system
    (BeOS) where undefined symbols in shared libraries is
    normal since the kernel patches them at load time to
    select which function is most appropriate for the
    current architecture.  I.E. 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.










                            ‐17‐


−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.

−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.









                            ‐18‐


    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.











                            ‐19‐


    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.











                            ‐20‐


−−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
    Use org as the starting address for−−−respectively−−−the









                            ‐21‐


    "bss", "data", or the "text" segment of the output file.
    org must be a single hexadecimal integer; for
    compatibility with other linkers, you may omit the
    leading 0x usually associated with hexadecimal values.

−−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
    heirarchy 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 practice, 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
    practice, 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









                            ‐22‐


        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









                            ‐23‐


    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.

−−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:









                            ‐24‐


            void *
            __wrap_malloc (int c)
            {
              printf ("malloc called with %ld\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.

−−base−file file
    Use file as the name of a file in which to save the base









                            ‐25‐


    addresses of all the relocations needed for generating
    DLLs with dlltool.

−−dll
    Create a DLL instead of a regular executable.  You may
    also use −shared or specify a "LIBRARY" in a given
    ".def" file.

−−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.

−−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".









                            ‐26‐


−−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.

−−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.

−−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.

−−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.

−−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.

−−kill−at
    If given, the stdcall suffixes (@nn) will be stripped
    from symbols before they are exported.

−−major−image−version value
    Sets the major number of the "image version".  Defaults
    to 1.

−−major−os−version value
    Sets the major number of the "os version".  Defaults to
    4.

−−major−subsystem−version value
    Sets the major number of the "subsystem version".
    Defaults to 4.

−−minor−image−version value
    Sets the minor number of the "image version".  Defaults
    to 0.









                            ‐27‐


−−minor−os−version value
    Sets the minor number of the "os version".  Defaults to
    0.

−−minor−subsystem−version value
    Sets the minor number of the "subsystem version".
    Defaults to 0.

−−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.

−−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 behavior makes it possible to
    skip a separate "dlltool" import library creation step.

−−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.

−−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.

−−dll−search−prefix string
    When linking dynamically to a dll without an import
    library, i search for "<string><basename>.dll" in
    preference to "lib<basename>.dll". This behavior 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".

−−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 DLLs with those DATA
    exports.  This generally will ’just work’ ‐‐ but
    sometimes you may see this message:

    "variable ’<var>’ can’t be auto−imported. Please read









                            ‐28‐


    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 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 second method of dealing with this difficulty is to
    abandon ’auto−import’ for the offending symbol and mark
    it with "__declspec(dllimport)".  However, in practice
    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









                            ‐29‐


    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 third 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).

−−disable−auto−import
    Do not attempt to do sophisticalted linking of "_symbol"
    to "__imp__symbol" for DATA imports from DLLs.











                            ‐30‐


−−enable−extra−pe−debug
    Show additional debug info related to auto‐import symbol
    thunking.

−−section−alignment
    Sets the section alignment.  Sections in memory will
    always begin at addresses which are a multiple of this
    number.  Defaults to 0x1000.

−−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.

−−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.

You can change the behavior 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.











                            ‐31‐


     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.

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

Copyright (c) 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000,
2001 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".