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+# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
+# file Copyright.txt or https://cmake.org/licensing for details.
+
+#[=======================================================================[.rst:
+CheckLinkerFlag
+---------------
+
+Check whether the compiler supports a given link flag.
+
+.. command:: check_linker_flag
+
+ .. code-block:: cmake
+
+ check_linker_flag(<lang> <flag> <var>)
+
+Check that the link ``<flag>`` is accepted by the ``<lang>`` compiler without
+a diagnostic. Stores the result in an internal cache entry named ``<var>``.
+
+This command temporarily sets the ``CMAKE_REQUIRED_LINK_OPTIONS`` variable
+and calls the ``check_<lang>_source_compiles`` macro from the
+``Check<lang>SourceCompiles`` module (:module:`CheckCSourceCompiles`,
+:module:`CheckCSourceCompiles`, :module:`CheckCXXSourceCompiles`,
+:module:`CheckOBJCSourceCompiles`, :module:`CheckOBJCXXSourceCompiles` or
+:module:`CheckFortranSourceCompiles`). See documentation of these
+modules for a listing of variables that can otherwise modify the build.
+
+The underlying implementation rely on :prop_tgt:`LINK_OPTIONS` property to
+check the specified flag. The ``LINKER:`` prefix, as described in
+:command:`target_link_options` command, can be used as well.
+
+A positive result from this check indicates only that the compiler did not
+issue a diagnostic message when given the link flag. Whether the flag has any
+effect or even a specific one is beyond the scope of this module.
+
+.. note::
+ Since the :command:`try_compile` command forwards flags from variables
+ like :variable:`CMAKE_<LANG>_FLAGS`, unknown flags in such variables may
+ cause a false negative for this check.
+#]=======================================================================]
+
+include_guard(GLOBAL)
+
+include(CMakeCheckCompilerFlagCommonPatterns)
+
+function(CHECK_LINKER_FLAG _lang _flag _var)
+ get_property (_supported_languages GLOBAL PROPERTY ENABLED_LANGUAGES)
+ if (NOT _lang IN_LIST _supported_languages)
+ message (SEND_ERROR "check_linker_flag: ${_lang}: unknown language.")
+ return()
+ endif()
+
+ include (Check${_lang}SourceCompiles)
+
+ set(CMAKE_REQUIRED_LINK_OPTIONS "${_flag}")
+
+ # Normalize locale during test compilation.
+ set(_locale_vars LC_ALL LC_MESSAGES LANG)
+ foreach(v IN LISTS _locale_vars)
+ set(_locale_vars_saved_${v} "$ENV{${v}}")
+ set(ENV{${v}} C)
+ endforeach()
+
+ if (_lang MATCHES "^(C|CXX)$")
+ set (_source "int main() { return 0; }")
+ elseif (_lang STREQUAL "Fortran")
+ set (_source " program test\n stop\n end program")
+ elseif (_lang MATCHES "^(OBJC|OBJCXX)$")
+ set (_source "#ifndef __OBJC__\n# error \"Not an Objective-C++ compiler\"\n#endif\nint main(void) { return 0; }")
+ else()
+ message (SEND_ERROR "check_linker_flag: ${_lang}: unsupported language.")
+ return()
+ endif()
+ check_compiler_flag_common_patterns(_common_patterns)
+
+ cmake_language (CALL check_${_lang}_source_compiles "${_source}" ${_var} ${_common_patterns})
+
+ foreach(v IN LISTS _locale_vars)
+ set(ENV{${v}} ${_locale_vars_saved_${v}})
+ endforeach()
+ set(${_var} "${${_var}}" PARENT_SCOPE)
+endfunction()