The following options are supported.
Creates a 32-bit, or 64-bit object.
By default, the class of the object being generated is determined from the first ELF
object processed from the command line. If no objects are specified, the class is determined by the first object encountered within the first archive processed from the command line. If there are no objects or archives, the link-editor creates a 32-bit object.
option is required to create a 64-bit object solely from a mapfile.
options can also be used in the rare case of linking entirely from an archive that contains a mixture of 32 and 64-bit objects. If the first object in the archive is not the class of the object that is required to be created, then the -32
option can be used to direct the link-editor. See The 32-bit link-editor and 64-bit link-editor
in Linker and Libraries Guide
In static mode only, produces an executable object file. Undefined references are not permitted. This option is the default behavior for static mode. The -a option can not be used with the -r option. See Static Executables under DESCRIPTION.
In dynamic mode only, provides no special processing for dynamic executable relocations that reference symbols in shared objects. Without the -b
option, the link-editor applies techniques within a dynamic executable so that the text segment can remain read-only. One technique is the creation of special position-independent relocations for references to functions that are defined in shared objects. Another technique arranges for data objects that are defined in shared objects to be copied into the memory image of an executable at runtime.
option is intended for specialized dynamic objects and is not recommended for general use. Its use suppresses all specialized processing required to ensure an object's shareability, and can even prevent the relocation of 64-bit executables.
These options govern direct binding. -B direct
establishes direct binding information by recording the relationship between each symbol reference together with the dependency that provides the definition. In addition, direct binding information is established between each symbol reference and an associated definition within the object being created. The runtime linker uses this information to search directly for a symbol in the associated object rather than to carry out a default symbol search.
Direct binding information can only be established to dependencies specified with the link-edit. Thus, you should use the -z defs
option. Objects that wish to interpose on symbols in a direct binding environment should identify themselves as interposers with the -z interpose
option. The use of -B direct
enables -z lazyload
for all dependencies.
The -B nodirect
option prevents any direct binding to the interfaces offered by the object being created. The object being created can continue to directly bind to external interfaces by specifying the -z direct
option. See Appendix D, Direct Bindings,
in Linker and Libraries Guide
Options governing library inclusion. -B dynamic is valid in dynamic mode only. These options can be specified any number of times on the command line as toggles: if the -B static option is given, no shared objects are accepted until -B dynamic is seen. See the -l option.
Causes any global symbols, not assigned to a version definition, to be eliminated from the symbol table. Version definitions can be supplied by means of a mapfile to indicate the global symbols that should remain visible in the generated object. This option achieves the same symbol elimination as the auto-elimination directive that is available as part of a mapfile version definition. This option can be useful when combining versioned and non-versioned relocatable objects. See also the -B local option and the -B reduce option. See Defining Additional Symbols with a mapfile in Linker and Libraries Guide.
Establishes a shared object and its dependencies as a group. Objects within the group are bound to other members of the group at runtime. This mode is similar to adding the object to the process by using dlopen
(3C) with the RTLD_GROUP
mode. An object that has an explicit dependency on a object identified as a group, becomes a member of the group.
As the group must be self contained, use of the -B group
option also asserts the -z defs
Causes any global symbols, not assigned to a version definition, to be reduced to local. Version definitions can be supplied by means of a mapfile to indicate the global symbols that should remain visible in the generated object. This option achieves the same symbol reduction as the auto-reduction directive that is available as part of a mapfile version definition. This option can be useful when combining versioned and non-versioned relocatable objects. See also the -B eliminate option and the -B reduce option. See Defining Additional Symbols with a mapfile in Linker and Libraries Guide.
When generating a relocatable object, causes the reduction of symbolic information defined by any version definitions. Version definitions can be supplied by means of a mapfile to indicate the global symbols that should remain visible in the generated object. By default, when a relocatable object is generated, version definitions are only recorded in the output image. The actual reduction of symbolic information is carried out when the object is used in the construction of a dynamic executable or shared object. The -B reduce option is applied automatically when a dynamic executable or shared object is created.
In dynamic mode only. When building a shared object, binds references to global symbols to their definitions, if available, within the object. Normally, references to global symbols within shared objects are not bound until runtime, even if definitions are available. This model allows definitions of the same symbol in an executable or other shared object to override the object's own definition. ld
issues warnings for undefined symbols unless -z defs
The -B symbolic
option is intended for specialized dynamic objects and is not recommended for general use. To reduce the runtime relocation processing that is required an object, the creation of a version definition is recommended.
Records the configuration file name for use at runtime. Configuration files can be employed to alter default search paths, provide a directory cache, together with providing alternative object dependencies. See crle(1).
Demangles C++ symbol names displayed in diagnostic messages.
When -d y, the default, is specified, ld uses dynamic linking. When -d n is specified, ld uses static linking. See Static Executables under DESCRIPTION, and -B dynamic|static.
Prints debugging information as specified by each token, to the standard error. The special token help indicates the full list of tokens available. See Debugging Aids in Linker and Libraries Guide.
Sets the entry point address for the output file to be the symbol epsym.
Useful only when building a shared object. Specifies that the symbol table of the shared object is used as an auxiliary filter on the symbol table of the shared object specified by name. Multiple instances of this option are allowed. This option can not be combined with the -F option. See Generating Auxiliary Filters in Linker and Libraries Guide.
Useful only when building a shared object. Specifies that the symbol table of the shared object is used as a filter on the symbol table of the shared object specified by name. Multiple instances of this option are allowed. This option can not be combined with the -f option. See Generating Standard Filters in Linker and Libraries Guide.
In dynamic mode only, produces a shared object. Undefined symbols are allowed. See Chapter 4, Shared Objects, in Linker and Libraries Guide.
In dynamic mode only, when building a shared object, records name in the object's dynamic section. name is recorded in any dynamic objects that are linked with this object rather than the object's file system name. Accordingly, name is used by the runtime linker as the name of the shared object to search for at runtime. See Recording a Shared Object Name in Linker and Libraries Guide.
Ignores LD_LIBRARY_PATH. This option is useful when an LD_LIBRARY_PATH setting is in effect to influence the runtime library search, which would interfere with the link-editing being performed.
When building an executable, uses name as the path name of the interpreter to be written into the program header. The default in static mode is no interpreter. In dynamic mode, the default is the name of the runtime linker, ld.so.1(1). Either case can be overridden by -I name. exec(2) loads this interpreter when the a.out is loaded, and passes control to the interpreter rather than to the a.out directly.
Searches a library libx.so or libx.a, the conventional names for shared object and archive libraries, respectively. In dynamic mode, unless the -B static option is in effect, ld searches each directory specified in the library search path for a libx.so or libx.a file. The directory search stops at the first directory containing either. ld chooses the file ending in .so if -lx expands to two files with names of the form libx.so and libx.a. If no libx.so is found, then ld accepts libx.a. In static mode, or when the -B static option is in effect, ld selects only the file ending in .a. ld searches a library when the library is encountered, so the placement of -l is significant. See Linking With Additional Libraries in Linker and Libraries Guide.
to the library search directories. ld
searches for libraries first in any directories specified by the -L
options and then in the standard directories. This option is useful only if the option precedes the -l
options to which the -L
option applies. See Directories Searched by the Link-Editor
in Linker and Libraries Guide
The environment variable LD_LIBRARY_PATH
can be used to supplement the library search path, however the -L
option is recommended, as the environment variable is also interpreted by the runtime environment. See LD_LIBRARY_PATH
under ENVIRONMENT VARIABLES.
Produces a memory map or listing of the input/output sections, together with any non-fatal multiply-defined symbols, on the standard output.
Reads mapfile as a text file of directives to ld. This option can be specified multiple times. If mapfile is a directory, then all regular files, as defined by stat(2), within the directory are processed. See Chapter 9, Mapfile Option, in Linker and Libraries Guide. Example mapfiles are provided in /usr/lib/ld. See FILES.
This option causes a DT_NEEDED entry to be added to the .dynamic section of the object being built. The value of the DT_NEEDED string is the string that is specified on the command line. This option is position dependent, and the DT_NEEDED .dynamic entry is relative to the other dynamic dependencies discovered on the link-edit line. This option is useful for specifying dependencies within device driver relocatable objects when combined with the -dy and -r options.
Produces an output object file that is named outfile. The name of the default object file is a.out.
Identifies an audit library, auditlib. This audit library is used to audit the object being created at runtime. A shared object identified as requiring auditing with the -p option, has this requirement inherited by any object that specifies the shared object as a dependency. See the -P option. See Runtime Linker Auditing Interface in Linker and Libraries Guide.
Identifies an audit library, auditlib. This audit library is used to audit the dependencies of the object being created at runtime. Dependency auditing can also be inherited from dependencies that are identified as requiring auditing. See the -p option, and the -z globalaudit option. See Runtime Linker Auditing Interface in Linker and Libraries Guide.
Under -Q y, an ident string is added to the .comment section of the output file. This string identifies the version of the ld used to create the file. This results in multiple ld idents when there have been multiple linking steps, such as when using ld -r. This identification is identical with the default action of the cc command. -Q n suppresses version identification. .comment sections can be manipulated by the mcs(1) utility.
Combines relocatable object files to produce one relocatable object file. ld does not complain about unresolved references. This option cannot be used with the -a option.
A colon-separated list of directories used to specify library search directories to the runtime linker. If present and not NULL, the path is recorded in the output object file and passed to the runtime linker. Multiple instances of this option are concatenated together with each path
separated by a colon. See Directories Searched by the Runtime Linker
in Linker and Libraries Guide
The use of a runpath within an associated object is preferable to setting global search paths such as through the LD_LIBRARY_PATH
environment variable. Only the runpaths that are necessary to find the objects dependencies should be recorded. ldd
(1) can also be used to discover unused runpaths in dynamic objects, when used with the -U
Various tokens can also be supplied with a runpath that provide a flexible means of identifying system capabilities or an objects location. See Appendix C, Establishing Dependencies with Dynamic String Tokens,
in Linker and Libraries Guide
. The $ORIGIN
token is especially useful in allowing dynamic objects to be relocated to different locations in the file system.
Strips symbolic information from the output file. Any debugging information, that is, .line, .debug*, and .stab* sections, and their associated relocation entries are removed. Except for relocatable files, a symbol table SHT_SYMTAB and its associated string table section are not created in the output object file. The elimination of a SHT_SYMTAB symbol table can reduce the .stab* debugging information that is generated using the compiler drivers -g option. See the -z redlocsym and -z noldynsym options.
The shared object supportlib is loaded with ld and given information regarding the linking process. Shared objects that are defined by using the -S option can also be supplied using the SGS_SUPPORT environment variable. See Link-Editor Support Interface in Linker and Libraries Guide.
Turns off the warning for multiply-defined symbols that have different sizes or different alignments.
Enters symname as an undefined symbol in the symbol table. This option is useful for loading entirely from an archive library. In this instance, an unresolved reference is needed to force the loading of the first routine. The placement of this option on the command line is significant. This option must be placed before the library that defines the symbol. See Defining Additional Symbols with the u option in Linker and Libraries Guide.
Outputs a message giving information about the version of ld being used.
Changes the default directories used for finding libraries. dirlist is a colon-separated path list.
Useful only when building a dynamic executable. Specifies that references to external absolute symbols should be resolved immediately instead of being left for resolution at runtime. In very specialized circumstances, this option removes text relocations that can result in excessive swap space demands by an executable.
Alters the extraction criteria of objects from any archives that follow. By default, archive members are extracted to satisfy undefined references and to promote tentative definitions with data definitions. Weak symbol references do not trigger extraction. Under the -z allextract or --whole-archive options, all archive members are extracted from the archive. Under -z weakextract, weak references trigger archive extraction. The -z defaultextract or --no-whole-archive options provide a means of returning to the default following use of the former extract options. See Archive Processing in Linker and Libraries Guide.
Execute the 64-bit ld. The creation of very large 32-bit objects can exhaust the virtual memory that is available to the 32-bit ld. The -z altexec64 option can be used to force the use of the associated 64-bit ld. The 64-bit ld provides a larger virtual address space for building 32-bit objects. See The 32-bit link-editor and 64-bit link-editor in Linker and Libraries Guide.
By default, ld
combines multiple relocation sections when building executables or shared objects. This section combination differs from relocatable objects, in which relocation sections are maintained in a one-to-one relationship with the sections to which the relocations must be applied. The -z nocombreloc
option disables this merging of relocation sections, and preserves the one-to-one relationship found in the original relocatable objects.
sorts the entries of data relocation sections by their symbol reference. This sorting reduces runtime symbol lookup. When multiple relocation sections are combined, this sorting produces the least possible relocation overhead when objects are loaded into memory, and speeds the runtime loading of dynamic objects.
Historically, the individual relocation sections were carried over to any executable or shared object, and the -z combreloc
option was required to enable the relocation section merging previously described. Relocation section merging is now the default. The -z combreloc
option is still accepted for the benefit of old build environments, but the option is unnecessary, and has no effect.
Enables warnings that check the location of where libraries passed in with -l are found. If the link-editor finds a library on its default search path it will emit a warning. This warning can be made fatal in conjunction with the option -z fatal-warnings. Passing libname white lists a library from this check. The library must be the full name of the library, e.g. libc.so. To white list multiple libraries, the -z assert-deflib=libname option can be repeated multiple times. This option is useful when trying to build self-contained objects where a referenced library might exist in the default system library path and in alternate paths specified by -L, but you only want the alternate paths to be used.
The -z defs
option and the --no-undefined
option force a fatal error if any undefined symbols remain at the end of the link. This mode is the default when an executable is built. For historic reasons, this mode is not
the default when building a shared object. Use of the -z defs
option is recommended, as this mode assures the object being built is self-contained. A self-contained object has all symbolic references resolved internally, or to the object's immediate dependencies.
The -z nodefs
option allows undefined symbols. For historic reasons, this mode is the default when a shared object is built. When used with executables, the behavior of references to such undefined symbols is unspecified. Use of the -z nodefs
option is not recommended.
Enables or disables direct binding to any dependencies that follow on the command line. These options allow finer control over direct binding than the global counterpart -B direct. The -z direct option also differs from the -B direct option in the following areas. Direct binding information is not established between a symbol reference and an associated definition within the object being created. Lazy loading is not enabled.
Marks a filtee so that when processed by a filter, the filtee terminates any further filtee searches by the filter. See Reducing Filtee Searches in Linker and Libraries Guide.
Controls the behavior of warnings emitted from the link-editor. Setting -z fatal-warnings promotes warnings emitted by the link-editor to fatal errors that will cause the link-editor to fail before linking. -z nofatal-warnings instead demotes these warnings such that they will not cause the link-editor to exit prematurely.
Appends an entry to the .finiarray section of the object being built. If no .finiarray section is present, a section is created. The new entry is initialized to point to function. See Initialization and Termination Sections in Linker and Libraries Guide.
This option supplements an audit library definition that has been recorded with the -P
option. This option is only meaningful when building a dynamic executable. Audit libraries that are defined within an object with the -P
option typically allow for the auditing of the immediate dependencies of the object. The -z globalaudit
promotes the auditor to a global auditor, thus allowing the auditing of all dependencies. See Invoking the Auditing Interface
in Linker and Libraries Guide
An auditor established with the -P
option and the -z globalaudit
option, is equivalent to the auditor being established with the LD_AUDIT
environment variable. See ld.so.1
Assigns, or deassigns each dependency that follows to a unique group. The assignment of a dependency to a group has the same effect as if the dependency had been built using the -B group option.
Give messages suggesting link-editor features that could improve the resulting dynamic object.
Specific classes of suggestion can be silenced by specifying an optional comma separated list of guidance identifiers.
The current classes of suggestion provided are:
Enable use of direct binding
Suggests that -z direct
or -B direct
be present prior to any specified dependency. This allows predictable symbol binding at runtime.
Can be disabled with -z guidance=nodirect
Enable lazy dependency loading
Suggests that -z lazyload
be present prior to any specified dependency. This allows the dynamic object to be loaded more quickly.
Can be disabled with -z guidance=nolazyload
Shared objects should define all their dependencies.
Suggests that -z defs
be specified on the link-editor command line. Shared objects that explicitly state all their dependencies behave more predictably when used.
Can be be disabled with -z guidance=nodefs
Version 2 mapfile syntax
Suggests that any specified mapfiles use the more readable version 2 syntax.
Can be disabled with -z guidance=nomapfile
Read-only text segment
Should any runtime relocations within the text segment exist, suggests that the object be compiled with position independent code (PIC). Keeping large allocatable sections read-only allows them to be shared between processes using a given shared object.
Can be disabled with -z guidance=notext
No unused dependencies
Suggests that any dependency not referenced by the resulting dynamic object be removed from the link-editor command line.
Can be disabled with -z guidance=nounused
Print a summary of the command line options on the standard output and exit.
Ignores, or records, dynamic dependencies that are not referenced as part of the link-edit. Ignores, or records, unreferenced ELF
sections from the relocatable objects that are read as part of the link-edit. By default, -z record
is in effect.
If an ELF
section is ignored, the section is eliminated from the output file being generated. A section is ignored when three conditions are true. The eliminated section must contribute to an allocatable segment. The eliminated section must provide no global symbols. No other section from any object that contributes to the link-edit, must reference an eliminated section.
Appends an entry to the .initarray section of the object being built. If no .initarray section is present, a section is created. The new entry is initialized to point to function. See Initialization and Termination Sections in Linker and Libraries Guide.
Marks the object so that its runtime initialization occurs before the runtime initialization of any other objects brought into the process at the same time. In addition, the object runtime finalization occurs after the runtime finalization of any other objects removed from the process at the same time. This option is only meaningful when building a shared object.
Marks the object as an interposer. At runtime, an object is identified as an explicit interposer if the object has been tagged using the -z interpose option. An explicit interposer is also established when an object is loaded using the LD_PRELOAD environment variable. Implicit interposition can occur because of the load order of objects, however, this implicit interposition is unknown to the runtime linker. Explicit interposition can ensure that interposition takes place regardless of the order in which objects are loaded. Explicit interposition also ensures that the runtime linker searches for symbols in any explicit interposers when direct bindings are in effect.
Enables or disables the marking of dynamic dependencies to be lazily loaded. Dynamic dependencies which are marked lazyload are not loaded at initial process start-up. These dependencies are delayed until the first binding to the object is made. Note: Lazy loading requires the correct declaration of dependencies, together with associated runpaths for each dynamic object used within a process. See Lazy Loading of Dynamic Dependencies in Linker and Libraries Guide.
The class of the link-editor is affected by the class of the output file being created and by the capabilities of the underlying operating system. The -z ld
] options provide a means of defining any link-editor argument. The defined argument is only interpreted, respectively, by the 32-bit class or 64-bit class of the link-editor.
For example, support libraries are class specific, so the correct class of support library can be ensured using:
ld ... -z ld32=-Saudit32.so.1 -z ld64=-Saudit64.so.1 ...
The class of link-editor that is invoked is determined from the ELF
class of the first relocatable file that is seen on the command line. This determination is carried out prior
to any -z ld
Marks a filter to indicate that filtees must be processed immediately at runtime. Normally, filter processing is delayed until a symbol reference is bound to the filter. The runtime processing of an object that contains this flag mimics that which occurs if the LD_LOADFLTR environment variable is in effect. See the ld.so.1(1).
Allows multiple symbol definitions. By default, multiple symbol definitions that occur between relocatable objects result in a fatal error condition. This option, suppresses the error condition, allowing the first symbol definition to be taken.
Allows multiple inclusion of the same file. By default, a warning is generated for libraries that are passed multiple times on the command line. This option suppresses that warning, allowing -z fatal-warnings to be used when compiling code that makes multiple inclusions. Note: When a file is specified more than once, only the first instance is included.
Disables the compression of ELF string tables. By default, string compression is applied to SHT_STRTAB sections, and to SHT_PROGBITS sections that have their SHF_MERGE and SHF_STRINGS section flags set.
Marks the object so that the runtime default library search path, used after any LD_LIBRARY_PATH or runpaths, is ignored. This option implies that all dependencies of the object can be satisfied from its runpath.
Marks the object as non-deletable at runtime. This mode is similar to adding the object to the process by using dlopen(3C) with the RTLD_NODELETE mode.
Marks the object as not available to dlopen(3C), either as the object specified by the dlopen(), or as any form of dependency required by the object specified by the dlopen(). This option is only meaningful when building a shared object.
Marks the object as not available to dldump(3C).
Prevents the inclusion of a .SUNW_ldynsym
section in dynamic executables or sharable libraries. The .SUNW_ldynsym
section augments the .dynsym
section by providing symbols for local functions. Local function symbols allow debuggers to display local function names in stack traces from stripped programs. Similarly, dladdr
(3C) is able to supply more accurate results.
The -z noldynsym
option also prevents the inclusion of the two symbol sort sections that are related to the .SUNW_ldynsym
section. The .SUNW_dynsymsort
section provides sorted access to regular function and variable symbols. The .SUNW_dyntlssort
section provides sorted access to thread local storage ( TLS
) variable symbols.
, and .SUNW_dyntlssort
sections, which becomes part of the allocable text segment of the resulting file, cannot be removed by strip
(1). Therefore, the -z noldynsym
option is the only way to prevent their inclusion. See the -s
and -z redlocsym
Partially initialized symbols, that are defined within relocatable object files, are expanded in the output file being generated.
Does not record any versioning sections. Any version sections or associated .dynamic section entries are not generated in the output image.
Marks the object as requiring non-lazy runtime binding. This mode is similar to adding the object to the process by using dlopen(3C) with the RTLD_NOW mode. This mode is also similar to having the LD_BIND_NOW environment variable in effect. See ld.so.1(1).
Marks the object as requiring immediate $ORIGIN processing at runtime. This option is only maintained for historic compatibility, as the runtime analysis of objects to provide for $ORIGIN processing is now default.
Appends an entry to the .preinitarray section of the object being built. If no .preinitarray section is present, a section is created. The new entry is initialized to point to function. See Initialization and Termination Sections in Linker and Libraries Guide.
Eliminates all local symbols except for the SECT symbols from the symbol table SHT_SYMTAB. All relocations that refer to local symbols are updated to refer to the corresponding SECT symbol. This option allows specialized objects to greatly reduce their symbol table sizes. Eliminated local symbols can reduce the .stab* debugging information that is generated using the compiler drivers -g option. See the -s and -z noldynsym options.
ld normally issues a fatal error upon encountering a relocation using a symbol that references an eliminated COMDAT section. If -z relaxreloc is enabled, ld instead redirects such relocations to the equivalent symbol in the COMDAT section that was kept. -z relaxreloc is a specialized option, mainly of interest to compiler authors, and is not intended for general use.
These options rescan the archive files that are provided to the link-edit. By default, archives are processed once as the archives appear on the command line. Archives are traditionally specified at the end of the command line so that their symbol definitions resolve any preceding references. However, specifying archives multiple times to satisfy their own interdependencies can be necessary.
is a positional option, and is processed by the link-editor immediately when encountered on the command line. All archives seen on the command line up to that point are immediately reprocessed in an attempt to locate additional archive members that resolve symbol references. This archive rescanning is repeated until a pass over the archives occurs in which no new members are extracted.
is a position independent option. The link-editor defers the rescan operation until after it has processed the entire command line, and then initiates a final rescan operation over all archives seen on the command line. The -z rescan
operation can interact incorrectly with objects that contain initialization (.init) or finalization (.fini) sections, preventing the code in those sections from running. For this reason, -z rescan
is deprecated, and use of -z rescan-now
... -z rescan-end
Defines an archive rescan group. This is a positional construct, and is processed by the link-editor immediately upon encountering the closing delimiter option. Archives found within the group delimiter options are reprocessed as a group in an attempt to locate additional archive members that resolve symbol references. This archive rescanning is repeated until a pass over the archives On the occurs in which no new members are extracted. Archive rescan groups cannot be nested.
Specifies the machine type for the output object. Supported targets are Sparc and x86. The 32-bit machine type for the specified target is used unless the -64 option is also present, in which case the corresponding 64-bit machine type is used. By default, the machine type of the object being generated is determined from the first ELF object processed from the command line. If no objects are specified, the machine type is determined by the first object encountered within the first archive processed from the command line. If there are no objects or archives, the link-editor assumes the native machine. This option is useful when creating an object directly with ld whose input is solely from a mapfile. See the -M option. It can also be useful in the rare case of linking entirely from an archive that contains objects of different machine types for which the first object is not of the desired machine type. See The 32-bit link-editor and 64-bit link-editor in Linker and Libraries Guide.
In dynamic mode only, forces a fatal error if any relocations against non-writable, allocatable sections remain. For historic reasons, this mode is not the default when building an executable or shared object. However, its use is recommended to ensure that the text segment of the dynamic object being built is shareable between multiple running processes. A shared text segment incurs the least relocation overhead when loaded into memory. See Position-Independent Code in Linker and Libraries Guide.
In dynamic mode only, allows relocations against all allocatable sections, including non-writable ones. This mode is the default when building a shared object.
In dynamic mode only, lists a warning if any relocations against non-writable, allocatable sections remain. This mode is the default when building an executable.
This option provides additional warning diagnostics during a link-edit. Presently, this option conveys suspicious use of displacement relocations. This option also conveys the restricted use of static TLS relocations when building shared objects. In future, this option might be enhanced to provide additional diagnostics that are deemed too noisy to be generated by default.
Rename undefined references to symbol
in order to allow wrapper code to be linked into the output object without having to modify source code. When -z wrap
is specified, all undefined references to symbol
are modified to reference __wrap_symbol
, and all references to __real_symbol
are modified to reference symbol
. The user is expected to provide an object containing the __wrap_symbol
function. This wrapper function can call __real_symbol
in order to reference the actual function being wrapped.
The following is an example of a wrapper for the malloc
(void) printf("malloc called with %zu\n", c);
If you link other code with this file using -z wrap=malloc
to compile all the objects, then all calls to malloc
will call the function __wrap_malloc
instead. The call to __real_malloc
will call the real malloc
The real and wrapped functions should be maintained in separate source files. Otherwise, the compiler or assembler may resolve the call instead of leaving that operation for the link-editor to carry out, and prevent the wrap from occurring.