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It must contain two elements.
::
<PREFIX> <SUFFIX>
``<PREFIX>`` and ``<SUFFIX>`` will be used to encapsulate the list of
libraries.
For the elements of this variable, the ``LINKER:`` prefix can be used:
.. include:: ../command/LINK_OPTIONS_LINKER.txt
:start-line: 3
Examples
^^^^^^^^
Solving cross-references between two static libraries
"""""""""""""""""""""""""""""""""""""""""""""""""""""
A common need is the capability to search repeatedly in a group of static
libraries until no new undefined references are created. This capability is
offered by different environments but with a specific syntax:
.. code-block:: cmake
set(CMAKE_C_LINK_GROUP_USING_cross_refs_SUPPORTED TRUE)
if(CMAKE_C_COMPILER_ID STREQUAL "GNU"
AND CMAKE_SYSTEM_NAME STREQUAL "Linux")
set(CMAKE_C_LINK_GROUP_USING_cross_refs "LINKER:--start-group"
"LINKER:--end-group")
elseif(CMAKE_C_COMPILER_ID STREQUAL "SunPro"
AND CMAKE_SYSTEM_NAME STREQUAL "SunOS")
set(CMAKE_C_LINK_GROUP_USING_cross_refs "LINKER:-z,rescan-start"
"LINKER:-z,rescan-end")
else()
# feature not yet supported for the other environments
set(CMAKE_C_LINK_GROUP_USING_cross_refs_SUPPORTED FALSE)
endif()
add_library(lib1 STATIC ...)
add_library(lib3 SHARED ...)
if(CMAKE_C_LINK_GROUP_USING_cross_refs_SUPPORTED)
target_link_libraries(lib3 PRIVATE "$<LINK_GROUP:cross_refs,lib1,external>")
else()
target_link_libraries(lib3 PRIVATE lib1 external)
endif()
CMake will generate the following link expressions:
* ``GNU``: ``-Wl,--start-group /path/to/lib1.a -lexternal -Wl,--end-group``
* ``SunPro``: ``-Wl,-z,rescan-start /path/to/lib1.a -lexternal -Wl,-z,rescan-end``
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