-b input-format
--format=input-format
the binary format for input object files that follow this option on the command line.
usually unnecesasry.
the name of a particular format supported by the BFD libraries. (list the formats with `objdump -i'.) See section BFD.
use this option for linking files with an unusual binary format. or 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 $GNUTARGET . Define the input format from a script, using the command TARGET; see section Option Commands.
| -d
-dc
-dp
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. See section Option Commands.
| -e entry
--entry=entry
explicit symbol for beginning execution. See section The Entry Point
| -E
--export-dynamic
creating a dynamically linked executable, add all symbols to the dynamic symbol table,
the set of symbols which are visible from dynamic objects at run time.
without this the dynamic symbol table will normally contain only those symbols which are referenced by some dynamic object mentioned in the link.
With dlopen to load a dynamic object which needs to refer back to the symbols defined by the program, rather than some other dynamic object, use this option when linking the program itself.
| -f
--auxiliary name
When creating an ELF shared object, set the internal DT_AUXILIARY field.
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 link a program against this filter object, 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. it will be used instead of the definition in the filter object.
The shared object name need not exist and may be used to provide an alternative implementation of certain functions,
for debugging or for machine specific performance.
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 to inform 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 link a program against this filter object, the dynamic linker will see the DT_FILTER field and will resolve symbols according to the symbol table of the filter object as usual, but it will link to the definitions found in the shared object name.
The filter object can be used to select a subset of the symbols provided by the object name.
The -b, --format, --oformat options, the TARGET command in linker scripts, and the GNUTARGET environment variable.
| --force-exe-suffix
Insure that output file has an .exe suffix. Useful when using unmodified Unix makefiles on a Microsoft Windows host
| -hname
| -soname=name
When creating an ELF shared object, set the internal DT_SONAME field. 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').
| -larchive
--library=archive
Add archive file archive to the list of files to link. 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 also searchs for libraries with extensions other than .a . 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.
A .so extension indicates a shared library.
The linker will search an archive only once, 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. See section Environment Variables. 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
Set the text segment to be read only, 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 not specified, the name `a.out' is used by default. The script command OUTPUT can also specify the output file name.
| -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 not specified, an absolute file is produced. When linking C++ programs, this option will not resolve references to constructors; to do that, use `-Ur'. 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 commandfile
--script=commandfile
Read link commands from the file commandfile. These commands replace ld's default link script (rather than adding to it), so commandfile must specify everything necessary to describe the target format. You must use this option if you want to use a command which can only appear once in a linker script, such as the SECTIONS or MEMORY command. See section Command Language. If commandfile does not exist, 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.
| -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. 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
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.
| -assert keyword
ignored for SunOS compatibility.
-Bdynamic
| -dy
| -call_shared
Link against dynamic libraries. This is only meaningful on platforms for which shared libraries are supported. 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.
| -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. only meaningful on ELF platforms which support shared libraries.
| --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.
| --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 (see section Assignment: Defining Symbols). Note: there should be no white space between symbol, the equals sign ("="), and expression.
| --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.
| -EB
Link big-endian objects. This affects the default output format.
| -EL
Link little-endian objects. This affects the default output format.
| --embedded-relocs
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.
| --help
Print a summary of the command-line 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-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.
| --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. See section BFD.
| -qmagic
ignored for Linux compatibility.
| -Qy
ignored for SVR4 compatibility.
--relax
An option with machine dependent effects. only supported on a few targets. See section ld and the H8/300. See section ld and the Intel 960 family. 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 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. 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-relocateable 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. The linker uses the following search paths to locate required shared libraries.
Any directories specified by -rpath-link options.
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.
On an ELF system, if the -rpath and rpath-link options were not used, search the contents of the environment variable LD_RUN_PATH.
On SunOS, if the -rpath option was not used, search any directories specified using -L options.
For a native linker, the contents of the environment variable LD_LIBRARY_PATH.
The default directories, normally `/lib' and `/usr/lib'.
If the required shared library is not found, the linker will issue a warning and continue with the link.
| -shared
| -Bshareable | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |