Linux "ld" Command Line Options and Examples

The GNU linker

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.

Usage:

ld [options] objfile ...

Related Commands

Command Line Options:

-a

This option is supported for HP/UX compatibility. The keyword argument must be one of the strings archive, shared, or default.


                            ld -a ...

--audit

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


                            ld --audit ...

--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 thearchive-library search path.Future releases of ld may support similar functionality for other architecture families.


                            ld --architecture ...

--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 optionto specify the binary format for input object files that follow this option on the command line. Even when ld is configured tosupport alternative object formats, you don't usually need to specify this, as ld should be configured to expect as a defaultinput format the most usual format on each machine. input-format is a text string, the name of a particular format supported bythe 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 formatsexplicitly (when linking object files of different formats), by including -b input-format before each group of object files in aparticular 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";


                            ld --format ...

--mri-script

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; usethe -T option to run linker scripts written in the general-purpose ld scripting language. If MRI-cmdfile does not exist, ldlooks for it in the directories specified by any -L options.


                            ld --mri-script ...

-P

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


                            ld -P ...

--entry

Use entry as the explicit symbol for beginning execution of your program, rather than the default entry point. If there is nosymbol named entry, the linker will try to parse entry as a number, and use that as the entry address (the number will beinterpreted in base 10; you may use a leading 0x for base 16, or a leading 0 for base 8).


                            ld --entry ...

--exclude-libs

Specifies a list of archive libraries from which symbols should not be automatically exported. The library names may bedelimited by commas or colons. Specifying "--exclude-libs ALL" excludes symbols in all archive libraries from automatic export.This option is available only for the i386 PE targeted port of the linker and for ELF targeted ports. For i386 PE, symbolsexplicitly listed in a .def file are still exported, regardless of this option. For ELF targeted ports, symbols affected by thisoption will be treated as hidden.


                            ld --exclude-libs ...

--exclude-modules-for-implib

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


                            ld --exclude-modules-for-implib ...

--no-export-dynamic

When creating a dynamically linked executable, using the -E option or the --export-dynamic option causes the linker to add allsymbols to the dynamic symbol table. The dynamic symbol table is the set of symbols which are visible from dynamic objects atrun time.If you do not use either of these options (or use the --no-export-dynamic option to restore the default behavior), the dynamicsymbol 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 someother dynamic object, then you will probably need to use this option when linking the program itself.You can also use the dynamic list to control what symbols should be added to the dynamic symbol table if the output formatsupports it. See the description of --dynamic-list.Note that this option is specific to ELF targeted ports. PE targets support a similar function to export all symbols from a DLLor EXE; see the description of --export-all-symbols below.


                            ld --no-export-dynamic ...

-EB

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


                            ld -EB ...

-EL

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


                            ld -EL ...

--auxiliary

When creating an ELF shared object, set the internal DT_AUXILIARY field to the specified name. This tells the dynamic linkerthat 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 theDT_AUXILIARY field. If the dynamic linker resolves any symbols from the filter object, it will first check whether there is adefinition in the shared object name. If there is one, it will be used instead of the definition in the filter object. Theshared object name need not exist. Thus the shared object name may be used to provide an alternative implementation of certainfunctions, 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 thecommand line.


                            ld --auxiliary ...

--filter

When creating an ELF shared object, set the internal DT_FILTER field to the specified name. This tells the dynamic linker thatthe symbol table of the shared object which is being created should be used as a filter on the symbol table of the shared objectname.If you later link a program against this filter object, then, when you run the program, the dynamic linker will see the DT_FILTERfield. The dynamic linker will resolve symbols according to the symbol table of the filter object as usual, but it will actuallylink to the definitions found in the shared object name. Thus the filter object can be used to select a subset of the symbolsprovided by the object name.Some older linkers used the -F option throughout a compilation toolchain for specifying object-file format for both input andoutput 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 creatingan ELF shared object.


                            ld --filter ...

-fini

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


                            ld -fini ...

-g

Ignored. Provided for compatibility with other tools.


                            ld -g ...

--gpsize

Set the maximum size of objects to be optimized using the GP register to size. This is only meaningful for object file formatssuch as MIPS ELF that support putting large and small objects into different sections. This is ignored for other object fileformats.


                            ld --gpsize ...

-soname

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


                            ld -soname ...

-i

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


                            ld -i ...

-init

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


                            ld -init ...

--library

Add the archive or object file specified by namespec to the list of files to link. This option may be used any number of times.If namespec is of the form :filename, ld will search the library path for a file called filename, otherwise it will search thelibrary path for a file called libnamespec.a.On systems which support shared libraries, ld may also search for files other than libnamespec.a. Specifically, on ELF and SunOSsystems, ld will search a directory for a library called libnamespec.so before searching for one called libnamespec.a. (Byconvention, a ".so" extension indicates a shared library.) Note that this behavior does not apply to :filename, which alwaysspecifies a file called filename.The linker will search an archive only once, at the location where it is specified on the command line. If the archive defines asymbol which was undefined in some object which appeared before the archive on the command line, the linker will include theappropriate file(s) from the archive. However, an undefined symbol in an object appearing later on the command line will notcause 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 fromthe behaviour of the AIX linker.


                            ld --library ...

--library-path

Add path searchdir to the list of paths that ld will search for archive libraries and ld control scripts. You may use thisoption any number of times. The directories are searched in the order in which they are specified on the command line.Directories specified on the command line are searched before the default directories. All -L options apply to all -l options,regardless of the order in which the options appear. -L options do not affect how ld searches for a linker script unless -Toption is specified.If searchdir begins with "=" or $SYSROOT, then this prefix will be replaced by the sysroot prefix, controlled by the --sysrootoption, or 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 somecases 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 atthe point in which the linker script appears in the command line.


                            ld --library-path ...

-m

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.


                            ld -m ...

--print-map

Print a link map to the standard output. A link map provides information about the link, including the following:· Where object files are mapped into memory.· How common symbols are allocated.· All archive members included in the link, with a mention of the symbol which caused the archive member to be brought in.· The values assigned to symbols.Note - symbols whose values are computed by an expression which involves a reference to a previous value of the same symbolmay not have correct result displayed in the link map. This is because the linker discards intermediate results and onlyretains the final value of an expression. Under such circumstances the linker will display the final value enclosed bysquare brackets. Thus for example a linker script containing:foo = 1foo = foo * 4foo = foo + 8will produce the following output in the link map if the -M option is used:0x00000001 foo = 0x1[0x0000000c] foo = (foo * 0x4)[0x0000000c] foo = (foo + 0x8)See Expressions for more information about expressions in linker scripts.


                            ld --print-map ...

--nmagic

Turn off page alignment of sections, and disable linking against shared libraries. If the output format supports Unix stylemagic numbers, mark the output as "NMAGIC".


                            ld --nmagic ...

--omagic

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


                            ld --omagic ...

--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 segmentto be page-aligned. Note - this option does not enable linking against shared libraries. Use -Bdynamic for this.


                            ld --no-omagic ...

--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. Thescript command "OUTPUT" can also specify the output file name.


                            ld --output ...

-O

If level is a numeric values greater than zero ld optimizes the output. This might take significantly longer and thereforeprobably should only be enabled for the final binary. At the moment this option only affects ELF shared library generation.Future releases of the linker may make more use of this option. Also currently there is no difference in the linker's behaviourfor different non-zero values of this option. Again this may change with future releases.


                            ld -O ...

-plugin

Involve a plugin in the linking process. The name parameter is the absolute filename of the plugin. Usually this parameter isautomatically added by the complier, when using link time optimization, but users can also add their own plugins if they so wish.Note that the location of the compiler originated plugins is different from the place where the ar, nm and ranlib programs searchfor their plugins. In order for those commands to make use of a compiler based plugin it must first be copied into the${libdir}/bfd-plugins directory. All gcc based linker plugins are backward compatible, so it is sufficient to just copy in thenewest one.


                            ld -plugin ...

--push-state

The --push-state allows to preserve the current state of the flags which govern the input file handling so that they can all berestored with one corresponding --pop-state option.The option which are covered are: -Bdynamic, -Bstatic, -dn, -dy, -call_shared, -non_shared, -static, -N, -n, --whole-archive,


                            ld --push-state ...

--no-whole-archive

One target for this option are specifications for pkg-config. When used with the --libs option all possibly needed libraries arelisted and then possibly linked with all the time. It is better to return something as follows:


                            ld --no-whole-archive ...

-Wl

--push-state --as-needed -libone -libtwo -Wl --pop-state


                            ld -Wl ...

--pop-state

Undoes the effect of --push-state, restores the previous values of the flags governing input file handling.


                            ld --pop-state ...

--emit-relocs

Leave relocation sections and contents in fully linked executables. Post link analysis and optimization tools may need thisinformation in order to perform correct modifications of executables. This results in larger executables.This option is currently only supported on ELF platforms.


                            ld --emit-relocs ...

--force-dynamic

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


                            ld --force-dynamic ...

--relocatable

Generate relocatable output---i.e., generate an output file that can in turn serve as input to ld. This is often called partiallinking. As a side effect, in environments that support standard Unix magic numbers, this option also sets the output file'smagic number to "OMAGIC". If this option is not specified, an absolute file is produced. When linking C++ programs, this optionwill 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 doesnot contain any relocations. Different output formats can have further restrictions; for example some "a.out"-based formats donot support partial linking with input files in other formats at all.This option does the same thing as -i.


                            ld --relocatable ...

--just-symbols

Read symbol names and their addresses from filename, but do not relocate it or include it in the output. This allows your outputfile 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 istreated as the -rpath option.


                            ld --just-symbols ...

--strip-all

Omit all symbol information from the output file.


                            ld --strip-all ...

--strip-debug

Omit debugger symbol information (but not all symbols) from the output file.


                            ld --strip-debug ...

--no-strip-discarded

Omit (or do not omit) global symbols defined in discarded sections. Enabled by default.


                            ld --no-strip-discarded ...

--trace

Print the names of the input files as ld processes them.


                            ld --trace ...

--script

Use scriptfile as the linker script. This script replaces ld's default linker script (rather than adding to it), so commandfilemust 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.


                            ld --script ...

--default-script

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


                            ld --default-script ...

--undefined

Force symbol to be entered in the output file as an undefined symbol. Doing this may, for example, trigger linking of additionalmodules from standard libraries. -u may be repeated with different option arguments to enter additional undefined symbols. Thisoption is equivalent to the "EXTERN" linker script command.If this option is being used to force additional modules to be pulled into the link, and if it is an error for the symbol toremain undefined, then the option --require-defined should be used instead.


                            ld --undefined ...

--require-defined

Require that symbol is defined in the output file. This option is the same as option --undefined except that if symbol is notdefined in the output file then the linker will issue an error and exit. The same effect can be achieved in a linker script byusing "EXTERN", "ASSERT" and "DEFINED" together. This option can be used multiple times to require additional symbols.


                            ld --require-defined ...

--orphan-handling

Control how orphan sections are handled. An orphan section is one not specifically mentioned in a linker script.MODE can have any of the following values:"place"Orphan sections are placed into a suitable output section following the strategy described in Orphan Sections. The option


                            ld --orphan-handling ...

--unique

"discard"All orphan sections are discarded, by placing them in the /DISCARD/ section."warn"The linker will place the orphan section as for "place" and also issue a warning."error"The linker will exit with an error if any orphan section is found.The default if --orphan-handling is not given is "place".


                            ld --unique ...

--unique[

Creates a separate output section for every input section matching SECTION, or if the optional wildcard SECTION argument ismissing, for every orphan input section. An orphan section is one not specifically mentioned in a linker script. You may usethis option multiple times on the command line; It prevents the normal merging of input sections with the same name, overridingoutput section assignments in a linker script.


                            ld --unique[ ...

-V

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


                            ld -V ...

--discard-all

Delete all local symbols.


                            ld --discard-all ...

--discard-locals

Delete all temporary local symbols. (These symbols start with system-specific local label prefixes, typically .L for ELF systemsor L for traditional a.out systems.)


                            ld --discard-locals ...

--trace-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 isnecessary 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.


                            ld --trace-symbol ...

-Y

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


                            ld -Y ...

-z

The recognized keywords are:bndpltAlways generate BND prefix in PLT entries. Supported for Linux/x86_64.call-nop=prefix-addrcall-nop=suffix-nopcall-nop=prefix-bytecall-nop=suffix-byteSpecify the 1-byte "NOP" padding when transforming indirect call to a locally defined function, foo, via its GOT slot.call-nop=prefix-addr generates "0x67 call foo". call-nop=suffix-nop generates "call foo 0x90". call-nop=prefix-bytegenerates "byte call foo". call-nop=suffix-byte generates "call foo byte". Supported for i386 and x86_64.combrelocnocombrelocCombine multiple dynamic relocation sections and sort to improve dynamic symbol lookup caching. Do not do this ifnocombreloc.commonnocommonGenerate common symbols with STT_COMMON type during a relocatable link. Use STT_OBJECT type if nocommon.common-page-size=valueSet the page size most commonly used to value. Memory image layout will be optimized to minimize memory pages if the systemis using pages of this size.defsReport unresolved symbol references from regular object files. This is done even if the linker is creating a non-symbolicshared library. This option is the inverse of -z undefs.dynamic-undefined-weaknodynamic-undefined-weakMake undefined weak symbols dynamic when building a dynamic object, if they are referenced from a regular object file and notforced local by symbol visibility or versioning. Do not make them dynamic if nodynamic-undefined-weak. If neither option isgiven, a target may default to either option being in force, or make some other selection of undefined weak symbols dynamic.Not all targets support these options.execstackMarks the object as requiring executable stack.globalThis option is only meaningful when building a shared object. It makes the symbols defined by this shared object availablefor symbol resolution of subsequently loaded libraries.globalauditThis option is only meaningful when building a dynamic executable. This option marks the executable as requiring globalauditing by setting the "DF_1_GLOBAUDIT" bit in the "DT_FLAGS_1" dynamic tag. Global auditing requires that any auditinglibrary defined via the --depaudit or -P command line options be run for all dynamic objects loaded by the application.ibtpltGenerate Intel Indirect Branch Tracking (IBT) enabled PLT entries. Supported for Linux/i386 and Linux/x86_64.ibt Generate GNU_PROPERTY_X86_FEATURE_1_IBT in .note.gnu.property section to indicate compatibility with IBT. This also impliesibtplt. Supported for Linux/i386 and Linux/x86_64.initfirstThis option is only meaningful when building a shared object. It marks the object so that its runtime initialization willoccur before the runtime initialization of any other objects brought into the process at the same time. Similarly theruntime finalization of the object will occur after the runtime finalization of any other objects.interposeSpecify that the dynamic loader should modify its symbol search order so that symbols in this shared library interpose allother shared libraries not so marked.lazyWhen generating an executable or shared library, mark it to tell the dynamic linker to defer function call resolution to thepoint when the function is called (lazy binding), rather than at load time. Lazy binding is the default.loadfltrSpecify that the object's filters be processed immediately at runtime.max-page-size=valueSet the maximum memory page size supported to value.muldefsAllow multiple definitions.nocopyrelocDisable linker generated .dynbss variables used in place of variables defined in shared libraries. May result in dynamictext relocations.nodefaultlibSpecify that the dynamic loader search for dependencies of this object should ignore any default library search paths.nodeleteSpecify that the object shouldn't be unloaded at runtime.nodlopenSpecify that the object is not available to "dlopen".nodumpSpecify that the object can not be dumped by "dldump".noexecstackMarks the object as not requiring executable stack.noextern-protected-dataDon't treat protected data symbols as external when building a shared library. This option overrides the linker backenddefault. It can be used to work around incorrect relocations against protected data symbols generated by compiler. Updateson protected data symbols by another module aren't visible to the resulting shared library. Supported for i386 and x86-64.noreloc-overflowDisable relocation overflow check. This can be used to disable relocation overflow check if there will be no dynamicrelocation overflow at run-time. Supported for x86_64.now When generating an executable or shared library, mark it to tell the dynamic linker to resolve all symbols when the programis started, or when the shared library is loaded by dlopen, instead of deferring function call resolution to the point whenthe function is first called.originSpecify that the object requires $ORIGIN handling in paths.relronorelroCreate an ELF "PT_GNU_RELRO" segment header in the object. This specifies a memory segment that should be made read-onlyafter relocation, if supported. Specifying common-page-size smaller than the system page size will render this protectionineffective. Don't create an ELF "PT_GNU_RELRO" segment if norelro.separate-codenoseparate-codeCreate separate code "PT_LOAD" segment header in the object. This specifies a memory segment that should contain onlyinstructions and must be in wholly disjoint pages from any other data. Don't create separate code "PT_LOAD" segment ifnoseparate-code is used.shstkGenerate GNU_PROPERTY_X86_FEATURE_1_SHSTK in .note.gnu.property section to indicate compatibility with Intel Shadow Stack.Supported for Linux/i386 and Linux/x86_64.stack-size=valueSpecify a stack size for an ELF "PT_GNU_STACK" segment. Specifying zero will override any default non-zero sized"PT_GNU_STACK" segment creation.textnotexttextoffReport an error if DT_TEXTREL is set, i.e., if the binary has dynamic relocations in read-only sections. Don't report anerror if notext or textoff.undefsDo not report unresolved symbol references from regular object files, either when creating an executable, or when creating ashared library. This option is the inverse of -z defs.Other keywords are ignored for Solaris compatibility.


                            ld -z ...

--start-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 searchedonly once in the order that it is specified on the command line. If a symbol in that archive is needed to resolve an undefinedsymbol referred to by an object in an archive that appears later on the command line, the linker would not be able to resolvethat 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 referencesbetween two or more archives.


                            ld --start-group ...

--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 theyare doing and deliberately wants to link in these unknown input files. This was the default behaviour of the linker, beforerelease 2.14. The default behaviour from release 2.14 onwards is to reject such input files, and so the


                            ld --no-accept-unknown-input-arch ...

--accept-unknown-input-arch

option has been added to restore the old behaviour.


                            ld --accept-unknown-input-arch ...

--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 thelibrary is actually needed or not. --as-needed causes a DT_NEEDED tag to only be emitted for a library that at that point in thelink satisfies a non-weak undefined symbol reference from a regular object file or, if the library is not found in the DT_NEEDEDlists of other needed libraries, a non-weak undefined symbol reference from another needed dynamic library. Object files orlibraries appearing on the command line after the library in question do not affect whether the library is seen as needed. Thisis similar to the rules for extraction of object files from archives. --no-as-needed restores the default behaviour.


                            ld --no-as-needed ...

--no-add-needed

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


                            ld --no-add-needed ...

-assert

This option is ignored for SunOS compatibility.


                            ld -assert ...

-call_shared

Link against dynamic libraries. This is only meaningful on platforms for which shared libraries are supported. This option isnormally the default on such platforms. The different variants of this option are for compatibility with various systems. Youmay use this option multiple times on the command line: it affects library searching for -l options which follow it.


                            ld -call_shared ...

-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 inthis object and its dependencies to be performed only inside the group. --unresolved-symbols=report-all is implied. This optionis only meaningful on ELF platforms which support shared libraries.


                            ld -Bgroup ...

-static

Do not link against shared libraries. This is only meaningful on platforms for which shared libraries are supported. Thedifferent variants of this option are for compatibility with various systems. You may use this option multiple times on thecommand line: it affects library searching for -l options which follow it. This option also implies


                            ld -static ...

-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 optioncan also be used with the --export-dynamic option, when creating a position independent executable, to bind references to globalsymbols to the definition within the executable. This option is only meaningful on ELF platforms which support shared librariesand position independent executables.


                            ld -Bsymbolic ...

-Bsymbolic-functions

When creating a shared library, bind references to global function symbols to the definition within the shared library, if any.This option can also be used with the --export-dynamic option, when creating a position independent executable, to bindreferences to global function symbols to the definition within the executable. This option is only meaningful on ELF platformswhich support shared libraries and position independent executables.


                            ld -Bsymbolic-functions ...

--dynamic-list

Specify the name of a dynamic list file to the linker. This is typically used when creating shared libraries to specify a listof global symbols whose references shouldn't be bound to the definition within the shared library, or creating dynamically linkedexecutables to specify a list of symbols which should be added to the symbol table in the executable. This option is onlymeaningful on ELF platforms which support shared libraries.The format of the dynamic list is the same as the version node without scope and node name. See VERSION for more information.


                            ld --dynamic-list ...

--dynamic-list-data

Include all global data symbols to the dynamic list.


                            ld --dynamic-list-data ...

--dynamic-list-cpp-new

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


                            ld --dynamic-list-cpp-new ...

--dynamic-list-cpp-typeinfo

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


                            ld --dynamic-list-cpp-typeinfo ...

--no-check-sections

Asks the linker not to check section addresses after they have been assigned to see if there are any overlaps. Normally thelinker will perform this check, and if it finds any overlaps it will produce suitable error messages. The linker does knowabout, and does make allowances for sections in overlays. The default behaviour can be restored by using the command line switch


                            ld --no-check-sections ...

--no-copy-dt-needed-entries

This option affects the treatment of dynamic libraries referred to by DT_NEEDED tags inside ELF dynamic libraries mentioned onthe command line. Normally the linker won't add a DT_NEEDED tag to the output binary for each library mentioned in a DT_NEEDEDtag in an input dynamic library. With --copy-dt-needed-entries specified on the command line however any dynamic libraries thatfollow it will have their DT_NEEDED entries added. The default behaviour can be restored with --no-copy-dt-needed-entries.This option also has an effect on the resolution of symbols in dynamic libraries. With --copy-dt-needed-entries dynamiclibraries mentioned on the command line will be recursively searched, following their DT_NEEDED tags to other libraries, in orderto resolve symbols required by the output binary. With the default setting however the searching of dynamic libraries thatfollow it will stop with the dynamic library itself. No DT_NEEDED links will be traversed to resolve symbols.


                            ld --no-copy-dt-needed-entries ...

--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 areprinted out, sorted by name. For each symbol, a list of file names is given. If the symbol is defined, the first file listed isthe location of the definition. If the symbol is defined as a common value then any files where this happens appear next.Finally any files that reference the symbol are listed.


                            ld --cref ...

--no-define-common

This option inhibits the assignment of addresses to common symbols. The script command "INHIBIT_COMMON_ALLOCATION" has the sameeffect.The --no-define-common option allows decoupling the decision to assign addresses to Common symbols from the choice of the outputfile type; otherwise a non-Relocatable output type forces assigning addresses to Common symbols. Using --no-define-common allowsCommon symbols that are referenced from a shared library to be assigned addresses only in the main program. This eliminates theunused duplicate space in the shared library, and also prevents any possible confusion over resolving to the wrong duplicate whenthere are many dynamic modules with specialized search paths for runtime symbol resolution.


                            ld --no-define-common ...

--force-group-allocation

This option causes the linker to place section group members like normal input sections, and to delete the section groups. Thisis the default behaviour for a final link but this option can be used to change the behaviour of a relocatable link (-r). Thescript command "FORCE_GROUP_ALLOCATION" has the same effect.


                            ld --force-group-allocation ...

--defsym

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


                            ld --defsym ...

--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. Theoptional demangling style argument can be used to choose an appropriate demangling style for your compiler. The linker willdemangle by default unless the environment variable COLLECT_NO_DEMANGLE is set. These options may be used to override thedefault.


                            ld --no-demangle ...

--dynamic-linker

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


                            ld --dynamic-linker ...

--no-dynamic-linker

When producing an executable file, omit the request for a dynamic linker to be used at load-time. This is only meaningful forELF executables that contain dynamic relocations, and usually requires entry point code that is capable of processing theserelocations.


                            ld --no-dynamic-linker ...

--embedded-relocs

This option is similar to the --emit-relocs option except that the relocs are stored in a target specific section. This optionis only supported by the BFIN, CR16 and M68K targets.


                            ld --embedded-relocs ...

--no-fatal-warnings

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


                            ld --no-fatal-warnings ...

--force-exe-suffix

Make sure that an output file has a .exe suffix.If a successfully built fully linked output file does not have a ".exe" or ".dll" suffix, this option forces the linker to copythe output file to one of the same name with a ".exe" suffix. This option is useful when using unmodified Unix makefiles on aMicrosoft Windows host, since some versions of Windows won't run an image unless it ends in a ".exe" suffix.


                            ld --force-exe-suffix ...

--no-gc-sections

Enable garbage collection of unused input sections. It is ignored on targets that do not support this option. The defaultbehaviour (of not performing this garbage collection) can be restored by specifying --no-gc-sections on the command line. Notethat garbage collection for COFF and PE format targets is supported, but the implementation is currently considered to beexperimental.


                            ld --no-gc-sections ...

--no-print-gc-sections

List all sections removed by garbage collection. The listing is printed on stderr. This option is only effective if garbagecollection has been enabled via the --gc-sections) option. The default behaviour (of not listing the sections that are removed)can be restored by specifying --no-print-gc-sections on the command line.


                            ld --no-print-gc-sections ...

--gc-keep-exported

When --gc-sections is enabled, this option prevents garbage collection of unused input sections that contain global symbolshaving default or protected visibility. This option is intended to be used for executables where unreferenced sections wouldotherwise be garbage collected regardless of the external visibility of contained symbols. Note that this option has no effectwhen linking shared objects since it is already the default behaviour. This option is only supported for ELF format targets.


                            ld --gc-keep-exported ...

--print-output-format

Print the name of the default output format (perhaps influenced by other command-line options). This is the string that wouldappear in an "OUTPUT_FORMAT" linker script command.


                            ld --print-output-format ...

--print-memory-usage

Print used size, total size and used size of memory regions created with the MEMORY command. This is useful on embedded targetsto have a quick view of amount of free memory. The format of the output has one headline and one line per region. It is bothhuman readable and easily parsable by tools. Here is an example of an output:Memory region Used Size Region Size %age UsedROM: 256 KB 1 MB 25.00%RAM: 32 B 2 GB 0.00%


                            ld --print-memory-usage ...

--help

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


                            ld --help ...

--target-help

Print a summary of all target specific options on the standard output and exit.


                            ld --target-help ...

-Map

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


                            ld -Map ...

--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 toinstead optimize for memory usage, by rereading the symbol tables as necessary. This may be required if ld runs out of memoryspace while linking a large executable.


                            ld --no-keep-memory ...

--no-allow-shlib-undefined

Allows or disallows undefined symbols in shared libraries. This switch is similar to --no-undefined except that it determinesthe behaviour when the undefined symbols are in a shared library rather than a regular object file. It does not affect howundefined symbols in regular object files are handled.The default behaviour is to report errors for any undefined symbols referenced in shared libraries if the linker is being used tocreate an executable, but to allow them if the linker is being used to create a shared library.The reasons for allowing undefined symbol references in shared libraries specified at link time are that:· A shared library specified at link time may not be the same as the one that is available at load time, so the symbol mightactually be resolvable at load time.· There are some operating systems, eg BeOS and HPPA, where undefined symbols in shared libraries are normal.The BeOS kernel for example patches shared libraries at load time to select whichever function is most appropriate for thecurrent architecture. This is used, for example, to dynamically select an appropriate memset function.


                            ld --no-allow-shlib-undefined ...

--no-undefined-version

Normally when a symbol has an undefined version, the linker will ignore it. This option disallows symbols with undefined versionand a fatal error will be issued instead.


                            ld --no-undefined-version ...

--default-symver

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


                            ld --default-symver ...

--default-imported-symver

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


                            ld --default-imported-symver ...

--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 theyhave been compiled for different processors or for different endiannesses. This option tells ld that it should silently permitsuch possible errors. This option should only be used with care, in cases when you have taken some special action that ensuresthat the linker errors are inappropriate.


                            ld --no-warn-mismatch ...

--no-warn-search-mismatch

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


                            ld --no-warn-search-mismatch ...

--noinhibit-exec

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


                            ld --noinhibit-exec ...

-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.


                            ld -nostdlib ...

--oformat

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


                            ld --oformat ...

--out-implib

Create an import library in file corresponding to the executable the linker is generating (eg. a DLL or ELF program). Thisimport library (which should be called "*.dll.a" or "*.a" for DLLs) may be used to link clients against the generated executable;this behaviour makes it possible to skip a separate import library creation step (eg. "dlltool" for DLLs). This option is onlyavailable for the i386 PE and ELF targetted ports of the linker.


                            ld --out-implib ...

--pic-executable

Create a position independent executable. This is currently only supported on ELF platforms. Position independent executablesare 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 theexecutable cannot be overridden by shared libraries.


                            ld --pic-executable ...

-qmagic

This option is ignored for Linux compatibility.


                            ld -qmagic ...

-Qy

This option is ignored for SVR4 compatibility.


                            ld -Qy ...

--no-relax

An option with machine dependent effects. This option is only supported on a few targets.On some platforms the --relax option performs target specific, global optimizations that become possible when the linker resolvesaddressing in the program, such as relaxing address modes, synthesizing new instructions, selecting shorter version of currentinstructions, and combining constant values.On some platforms these link time global optimizations may make symbolic debugging of the resulting executable impossible. Thisis 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.On platforms where --relax is accepted the option --no-relax can be used to disable the feature.


                            ld --no-relax ...

--retain-symbols-file

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


                            ld --retain-symbols-file ...

-rpath

Add a directory to the runtime library search path. This is used when linking an ELF executable with shared objects. All -rpatharguments are concatenated and passed to the runtime linker, which uses them to locate shared objects at runtime. The -rpathoption is also used when locating shared objects which are needed by shared objects explicitly included in the link; see thedescription of the -rpath-link option. If -rpath is not used when linking an ELF executable, the contents of the environmentvariable "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 path out of all the -Loptions it is given. If a -rpath option is used, the runtime search path will be formed exclusively using the -rpath options,ignoring the -L options. This can be useful when using gcc, which adds many -L options which may be on NFS mounted file systems.For compatibility with other ELF linkers, if the -R option is followed by a directory name, rather than a file name, it istreated as the -rpath option.


                            ld -rpath ...

-rpath-link

When using ELF or SunOS, one shared library may require another. This happens when an "ld -shared" link includes a sharedlibrary 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 locatethe required shared library and include it in the link, if it is not included explicitly. In such a case, the -rpath-link optionspecifies the first set of directories to search. The -rpath-link option may specify a sequence of directory names either byspecifying a list of names separated by colons, or by appearing multiple times.The tokens $ORIGIN and $LIB can appear in these search directories. They will be replaced by the full path to the directorycontaining the program or shared object in the case of $ORIGIN and either lib - for 32-bit binaries - or lib64 - for 64-bitbinaries - in the case of $LIB.The alternative form of these tokens - ${ORIGIN} and ${LIB} can also be used. The token $PLATFORM is not supported.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


                            ld -rpath-link ...

--with-sysroot

3. On an ELF system, for native linkers, if the -rpath and -rpath-link options were not used, search the contents of theenvironment variable "LD_RUN_PATH".4. On SunOS, if the -rpath option was not used, search any directories specified using -L options.5. For a native linker, search the contents of the environment variable "LD_LIBRARY_PATH".6. For a native ELF linker, the directories in "DT_RUNPATH" or "DT_RPATH" of a shared library are searched for shared librariesneeded 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.


                            ld --with-sysroot ...

-Bshareable

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


                            ld -Bshareable ...

--sort-common

This option tells ld to sort the common symbols by alignment in ascending or descending order when it places them in theappropriate output sections. The symbol alignments considered are sixteen-byte or larger, eight-byte, four-byte, two-byte, andone-byte. This is to prevent gaps between symbols due to alignment constraints. If no sorting order is specified, thendescending order is assumed.


                            ld --sort-common ...

--sort-section

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


                            ld --sort-section ...

--spare-dynamic-tags

This option specifies the number of empty slots to leave in the .dynamic section of ELF shared objects. Empty slots may beneeded by post processing tools, such as the prelinker. The default is 5.


                            ld --spare-dynamic-tags ...

--split-by-file[

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


                            ld --split-by-file[ ...

--split-by-reloc[

Tries to creates extra sections in the output file so that no single output section in the file contains more than countrelocations. This is useful when generating huge relocatable files for downloading into certain real time kernels with the COFFobject file format; since COFF cannot represent more than 65535 relocations in a single section. Note that this will fail towork with object file formats which do not support arbitrary sections. The linker will not split up individual input sectionsfor redistribution, so if a single input section contains more than count relocations one output section will contain that manyrelocations. count defaults to a value of 32768.


                            ld --split-by-reloc[ ...

--stats

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


                            ld --stats ...

--sysroot

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


                            ld --sysroot ...

--task-link

This is used by COFF/PE based targets to create a task-linked object file where all of the global symbols have been converted tostatics.


                            ld --task-link ...

--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 touse 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 withfull 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.


                            ld --traditional-format ...

--section-start

Locate a section in the output file at the absolute address given by org. You may use this option as many times as necessary tolocate 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 betweensectionname, the equals sign ("="), and org.


                            ld --section-start ...

-Ttext

Same as --section-start, with ".bss", ".data" or ".text" as the sectionname.


                            ld -Ttext ...

-Ttext-segment

When creating an ELF executable, it will set the address of the first byte of the text segment.


                            ld -Ttext-segment ...

-Trodata-segment

When creating an ELF executable or shared object for a target where the read-only data is in its own segment separate from theexecutable text, it will set the address of the first byte of the read-only data segment.


                            ld -Trodata-segment ...

-Tldata-segment

When creating an ELF executable or shared object for x86-64 medium memory model, it will set the address of the first byte of theldata segment.


                            ld -Tldata-segment ...

--unresolved-symbols

Determine how to handle unresolved symbols. There are four possible values for method:ignore-allDo not report any unresolved symbols.report-allReport all unresolved symbols. This is the default.ignore-in-object-filesReport unresolved symbols that are contained in shared libraries, but ignore them if they come from regular object files.ignore-in-shared-libsReport unresolved symbols that come from regular object files, but ignore them if they come from shared libraries. This canbe useful when creating a dynamic binary and it is known that all the shared libraries that it should be referencing areincluded 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-symbolscan change this to a warning.


                            ld --unresolved-symbols ...

--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. If the optional NUMBER argument > 1, plugin symbol status will also bedisplayed.


                            ld --verbose[ ...

--version-script

Specify the name of a version script to the linker. This is typically used when creating shared libraries to specify additionalinformation about the version hierarchy for the library being created. This option is only fully supported on ELF platformswhich support shared libraries; see VERSION. It is partially supported on PE platforms, which can use version scripts to filtersymbol visibility in auto-export mode: any symbols marked local in the version script will not be exported.


                            ld --version-script ...

--warn-common

Warn when a common symbol is combined with another common symbol or with a symbol definition. Unix linkers allow this somewhatsloppy practice, but linkers on some other operating systems do not. This option allows you to find potential problems fromcombining global symbols. Unfortunately, some C libraries use this practice, so you may get some warnings about symbols in thelibraries 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 variablesomewhere.int i;A common symbol. If there are only (one or more) common symbols for a variable, it goes in the uninitialized data area ofthe output file. The linker merges multiple common symbols for the same variable into a single symbol. If they are ofdifferent sizes, it picks the largest size. The linker turns a common symbol into a declaration, if there is a definition ofthe same variable.The --warn-common option can produce five kinds of warnings. Each warning consists of a pair of lines: the first describes thesymbol just encountered, and the second describes the previous symbol encountered with the same name. One or both of the twosymbols 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 here2. Turning a common symbol into a reference, because a later definition for the symbol is encountered. This is the same as theprevious case, except that the symbols are encountered in a different order.<file>(<section>): warning: definition of `<symbol>'overriding common<file>(<section>): warning: common is here3. Merging a common symbol with a previous same-sized common symbol.<file>(<section>): warning: multiple commonof `<symbol>'<file>(<section>): warning: previous common is here4. 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 here5. Merging a common symbol with a previous smaller common symbol. This is the same as the previous case, except that thesymbols are encountered in a different order.<file>(<section>): warning: common of `<symbol>'overriding smaller common<file>(<section>): warning: smaller common is here


                            ld --warn-common ...

--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, thelinker can not detect the use of global constructors.


                            ld --warn-constructors ...

--warn-multiple-gp

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


                            ld --warn-multiple-gp ...

--warn-once

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


                            ld --warn-once ...

--warn-section-align

Warn if the address of an output section is changed because of alignment. Typically, the alignment will be set by an inputsection. The address will only be changed if it not explicitly specified; that is, if the "SECTIONS" command does not specify astart address for the section.


                            ld --warn-section-align ...

--warn-shared-textrel

Warn if the linker adds a DT_TEXTREL to a shared object.


                            ld --warn-shared-textrel ...

--warn-alternate-em

Warn if an object has alternate ELF machine code.


                            ld --warn-alternate-em ...

--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.


                            ld --warn-unresolved-symbols ...

--error-unresolved-symbols

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


                            ld --error-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 thelink, rather than searching the archive for the required object files. This is normally used to turn an archive file into ashared 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 toyour link and you may not want this flag to affect those as well.


                            ld --whole-archive ...

--wrap

Use a wrapper function for symbol. Any undefined reference to symbol will be resolved to "__wrap_symbol". Any undefinedreference 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 itwishes 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 dothis, you should not put the definition of "__real_malloc" in the same file as "__wrap_malloc"; if you do, the assembler mayresolve the call before the linker has a chance to wrap it to "malloc".


                            ld --wrap ...

--no-eh-frame-hdr

Request (--eh-frame-hdr) or suppress (--no-eh-frame-hdr) the creation of ".eh_frame_hdr" section and ELF "PT_GNU_EH_FRAME"segment header.


                            ld --no-eh-frame-hdr ...

--no-ld-generated-unwind-info

Request creation of ".eh_frame" unwind info for linker generated code sections like PLT. This option is on by default if linkergenerated unwind info is supported.


                            ld --no-ld-generated-unwind-info ...

--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


                            ld --disable-new-dtags ...

--enable-new-dtags

the new dynamic tags will be created as needed and older dynamic tags will be omitted. If you specify


                            ld --enable-new-dtags ...

--hash-size

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


                            ld --hash-size ...

--hash-style

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


                            ld --hash-style ...

--compress-debug-sections

On ELF platforms, these options control how DWARF debug sections are compressed using zlib.


                            ld --compress-debug-sections ...

--reduce-memory-overheads

This option reduces memory requirements at ld runtime, at the expense of linking speed. This was introduced to select the oldO(n^2) algorithm for link map file generation, rather than the new O(n) algorithm which uses about 40% more memory for symbolstorage.Another effect of the switch is to set the default hash table size to 1021, which again saves memory at the cost of lengtheningthe linker's run time. This is not done however if the --hash-size switch has been used.The --reduce-memory-overheads switch may be also be used to enable other tradeoffs in future versions of the linker.


                            ld --reduce-memory-overheads ...

--build-id

Request the creation of a ".note.gnu.build-id" ELF note section or a ".buildid" COFF section. The contents of the note areunique bits identifying this linked file. style can be "uuid" to use 128 random bits, "sha1" to use a 160-bit SHA1 hash on thenormative parts of the output contents, "md5" to use a 128-bit MD5 hash on the normative parts of the output contents, or"0xhexstring" to use a chosen bit string specified as an even number of hexadecimal digits ("-" and ":" characters between digitpairs are ignored). If style is omitted, "sha1" is used.The "md5" and "sha1" styles produces an identifier that is always the same in an identical output file, but will be unique amongall nonidentical output files. It is not intended to be compared as a checksum for the file's contents. A linked file may bechanged later by other tools, but the build ID bit string identifying the original linked file does not change.Passing "none" for style disables the setting from any "--build-id" options earlier on the command line.The i386 PE linker supports the -shared option, which causes the output to be a dynamically linked library (DLL) instead of a normalexecutable. 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 exportssymbols 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 thei386 PE target. Options that take values may be separated from their values by either a space or an equals sign.


                            ld --build-id ...

--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 specificto the i386 PE targeted port of the linker]


                            ld --add-stdcall-alias ...

--base-file

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


                            ld --base-file ...

--dll

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


                            ld --dll ...

--disable-long-section-names

The PE variants of the COFF object format add an extension that permits the use of section names longer than eight characters,the normal limit for COFF. By default, these names are only allowed in object files, as fully-linked executable images do notcarry the COFF string table required to support the longer names. As a GNU extension, it is possible to allow their use inexecutable images as well, or to (probably pointlessly!) disallow it in object files, by using these two options. Executableimages generated with these long section names are slightly non-standard, carrying as they do a string table, and may generateconfusing output when examined with non-GNU PE-aware tools, such as file viewers and dumpers. However, GDB relies on the use ofPE long section names to find Dwarf-2 debug information sections in an executable image at runtime, and so if neither option isspecified on the command-line, ld will enable long section names, overriding the default and technically correct behaviour, whenit finds the presence of debug information while linking an executable image and not stripping symbols. [This option is validfor all PE targeted ports of the linker]


                            ld --disable-long-section-names ...

--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 symbolthat differs only in the format of the symbol name (cdecl vs stdcall) and will resolve that symbol by linking to the match. Forexample, the undefined symbol "_foo" might be linked to the function "_foo@12", or the undefined symbol "_bar@16" might be linkedto the function "_bar". When the linker does this, it prints a warning, since it normally should have failed to link, butsometimes import libraries generated from third-party dlls may need this feature to be usable. If you specify


                            ld --disable-stdcall-fixup ...

--no-leading-underscore

For most targets default symbol-prefix is an underscore and is defined in target's description. By this option it is possible todisable/enable the default underscore symbol-prefix.


                            ld --no-leading-underscore ...

--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 ifthere otherwise wouldn't be any exported symbols. When symbols are explicitly exported via DEF files or implicitly exported viafunction 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 fromother 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. Symbolswhose names begin with "__rtti_" or "__builtin_" will not be exported, to help with C++ DLLs. Finally, there is an extensivelist of cygwin-private symbols that are not exported (obviously, this applies on when building DLLs for cygwin targets). Thesecygwin-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 isspecific to the i386 PE targeted port of the linker]


                            ld --export-all-symbols ...

--exclude-symbols

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]


                            ld --exclude-symbols ...

--exclude-all-symbols

Specifies no symbols should be automatically exported. [This option is specific to the i386 PE targeted port of the linker]


                            ld --exclude-all-symbols ...

--file-alignment

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


                            ld --file-alignment ...

--heap

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


                            ld --heap ...

--image-base

Use value as the base address of your program or dll. This is the lowest memory location that will be used when your program ordll is loaded. To reduce the need to relocate and improve performance of your dlls, each should have a unique base address andnot overlap any other dlls. The default is 0x400000 for executables, and 0x10000000 for dlls. [This option is specific to thei386 PE targeted port of the linker]


                            ld --image-base ...

--kill-at

If given, the stdcall suffixes (@nn) will be stripped from symbols before they are exported. [This option is specific to thei386 PE targeted port of the linker]


                            ld --kill-at ...

--large-address-aware

If given, the appropriate bit in the "Characteristics" field of the COFF header is set to indicate that this executable supportsvirtual addresses greater than 2 gigabytes. This should be used in conjunction with the /3GB or /USERVA=value megabytes switchin the "[operating systems]" section of the BOOT.INI. Otherwise, this bit has no effect. [This option is specific to PEtargeted ports of the linker]


                            ld --large-address-aware ...

--disable-large-address-aware

Reverts the effect of a previous --large-address-aware option. This is useful if --large-address-aware is always set by thecompiler driver (e.g. Cygwin gcc) and the executable does not support virtual addresses greater than 2 gigabytes. [This optionis specific to PE targeted ports of the linker]


                            ld --disable-large-address-aware ...

--major-image-version

Sets the major number of the "image version". Defaults to 1. [This option is specific to the i386 PE targeted port of thelinker]


                            ld --major-image-version ...

--major-os-version

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


                            ld --major-os-version ...

--major-subsystem-version

Sets the major number of the "subsystem version". Defaults to 4. [This option is specific to the i386 PE targeted port of thelinker]


                            ld --major-subsystem-version ...

--minor-image-version

Sets the minor number of the "image version". Defaults to 0. [This option is specific to the i386 PE targeted port of thelinker]


                            ld --minor-image-version ...

--minor-os-version

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


                            ld --minor-os-version ...

--minor-subsystem-version

Sets the minor number of the "subsystem version". Defaults to 0. [This option is specific to the i386 PE targeted port of thelinker]


                            ld --minor-subsystem-version ...

--output-def

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


                            ld --output-def ...

--enable-auto-image-base

Automatically choose the image base for DLLs, optionally starting with base value, unless one is specified using the


                            ld --enable-auto-image-base ...

--disable-auto-image-base

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


                            ld --disable-auto-image-base ...

--dll-search-prefix

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 PEtargeted port of the linker]


                            ld --dll-search-prefix ...

--enable-auto-import

Do sophisticated linking of "_symbol" to "__imp__symbol" for DATA imports from DLLs, and create the necessary thunking symbolswhen building the import libraries with those DATA exports. Note: Use of the 'auto-import' extension will cause the text sectionof the image file to be made writable. This does not conform to the PE-COFF format specification published by Microsoft.Note - use of the 'auto-import' extension will also cause read only data which would normally be placed into the .rdata sectionto be placed into the .data section instead. This is in order to work around a problem with consts that is described here:http://www.cygwin.com/ml/cygwin/2004-09/msg01101.htmlUsing '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 importtables only allow one). Instances where this may occur include accesses to member fields of struct variables imported from aDLL, as well as using a constant index into an array variable imported from a DLL. Any multiword variable (arrays, structs, longlong, etc) may trigger this error condition. However, regardless of the exact data type of the offending exported variable, ldwill 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 forruntime 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 avariable. Thus:extern type extern_array[];extern_array[1] -->{ volatile type *t=extern_array; t[1] }orextern 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 }orextern 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 practice that requires using compile-time #defines to indicate whether you are building aDLL, building client code that will link to the DLL, or merely building/linking to a static library. In making the choicebetween the various methods of resolving the 'direct address with constant offset' problem, you should consider typical real-world usage:Original:


                            ld --enable-auto-import ...

--foo.h

extern int arr[];


                            ld --foo.h ...

--foo.c

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


                            ld --foo.c ...

--disable-auto-import

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


                            ld --disable-auto-import ...

--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 tosuch data in your client code. [This option is specific to the i386 PE targeted port of the linker]


                            ld --enable-runtime-pseudo-reloc ...

--disable-runtime-pseudo-reloc

Do not create pseudo relocations for non-zero offset DATA imports from DLLs. [This option is specific to the i386 PE targetedport of the linker]


                            ld --disable-runtime-pseudo-reloc ...

--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 thelinker]


                            ld --enable-extra-pe-debug ...

--section-alignment

Sets the section alignment. Sections in memory will always begin at addresses which are a multiple of this number. Defaults to0x1000. [This option is specific to the i386 PE targeted port of the linker]


                            ld --section-alignment ...

--stack

Specify the number of bytes of memory to reserve (and optionally commit) to be used as stack for this program. The default is2MB reserved, 4K committed. [This option is specific to the i386 PE targeted port of the linker]


                            ld --stack ...

--subsystem

Specifies the subsystem under which your program will execute. The legal values for which are "native", "windows", "console","posix", and "xbox". You may optionally set the subsystem version also. Numeric values are also accepted for which. [Thisoption is specific to the i386 PE targeted port of the linker]The following options set flags in the "DllCharacteristics" field of the PE file header: [These options are specific to PEtargeted ports of the linker]


                            ld --subsystem ...

--high-entropy-va

Image is compatible with 64-bit address space layout randomization (ASLR).


                            ld --high-entropy-va ...

--dynamicbase

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


                            ld --dynamicbase ...

--forceinteg

Code integrity checks are enforced.


                            ld --forceinteg ...

--nxcompat

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


                            ld --nxcompat ...

--no-isolation

Although the image understands isolation, do not isolate the image.


                            ld --no-isolation ...

--no-seh

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


                            ld --no-seh ...

--no-bind

Do not bind this image.


                            ld --no-bind ...

--wdmdriver

The driver uses the MS Windows Driver Model.


                            ld --wdmdriver ...

--tsaware

The image is Terminal Server aware.


                            ld --tsaware ...

--no-insert-timestamp

Insert a real timestamp into the image. This is the default behaviour as it matches legacy code and it means that the image willwork with other, proprietary tools. The problem with this default is that it will result in slightly different images beingproduced each time the same sources are linked. The option --no-insert-timestamp can be used to insert a zero value for thetimestamp, this ensuring that binaries produced from identical sources will compare identically.The C6X uClinux target uses a binary format called DSBT to support shared libraries. Each shared library in the system needs to havea unique index; all executables use an index of 0.


                            ld --no-insert-timestamp ...

--dsbt-size

This option sets the number of entries in the DSBT of the current executable or shared library to size. The default is to createa table with 64 entries.


                            ld --dsbt-size ...

--dsbt-index

This option sets the DSBT index of the current executable or shared library to index. The default is 0, which is appropriate forgenerating executables. If a shared library is generated with a DSBT index of 0, the "R_C6000_DSBT_INDEX" relocs are copied intothe output file.The --no-merge-exidx-entries switch disables the merging of adjacent exidx entries in frame unwind info.The 68HC11 and 68HC12 linkers support specific options to control the memory bank switching mapping and trampoline code generation.


                            ld --dsbt-index ...

--no-trampoline

This option disables the generation of trampoline. By default a trampoline is generated for each far function which is calledusing a "jsr" instruction (this happens when a pointer to a far function is taken).


                            ld --no-trampoline ...

--bank-window

This option indicates to the linker the name of the memory region in the MEMORY specification that describes the memory bankwindow. The definition of such region is then used by the linker to compute paging and addresses within the memory window.The following options are supported to control handling of GOT generation when linking for 68K targets.


                            ld --bank-window ...

--got

This option tells the linker which GOT generation scheme to use. type should be one of single, negative, multigot or target.For more information refer to the Info entry for ld.The following options are supported to control microMIPS instruction generation and branch relocation checks for ISA mode transitionswhen linking for MIPS targets.


                            ld --got ...

--no-insn32

These options control the choice of microMIPS instructions used in code generated by the linker, such as that in the PLT or lazybinding stubs, or in relaxation. If --insn32 is used, then the linker only uses 32-bit instruction encodings. By default or if


                            ld --no-insn32 ...

--no-ignore-branch-isa

These options control branch relocation checks for invalid ISA mode transitions. If --ignore-branch-isa is used, then the linkeraccepts any branch relocations and any ISA mode transition required is lost in relocation calculation, except for some cases of"BAL" instructions which meet relaxation conditions and are converted to equivalent "JALX" instructions as the associatedrelocation is calculated. By default or if --no-ignore-branch-isa is used a check is made causing the loss of an ISA modetransition to produce an error.ENVIRONMENTYou 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 theBFD 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 oftensucceeds, but there are potential ambiguities, since there is no method of ensuring that the magic number used to specify object-fileformats is unique. However, the configuration procedure for BFD on each system places the conventional format for that system firstin 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 linkerbehaviour, particularly the default linker script. You can list the available emulations with the --verbose or -V options. If the


                            ld --no-ignore-branch-isa ...