You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
118 lines
3.9 KiB
118 lines
3.9 KiB
# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
|
|
# file Copyright.txt or https://cmake.org/licensing for details.
|
|
|
|
#[=======================================================================[.rst:
|
|
CheckFunctionExists
|
|
-------------------
|
|
|
|
Check once if a C function can be linked from system libraries.
|
|
|
|
.. command:: check_function_exists
|
|
|
|
.. code-block:: cmake
|
|
|
|
check_function_exists(<function> <variable>)
|
|
|
|
Checks that the ``<function>`` is provided by libraries on the system and store
|
|
the result in internal cache variable ``<variable>``.
|
|
|
|
The following variables may be set before calling this macro to modify the
|
|
way the check is run:
|
|
|
|
.. include:: /module/CMAKE_REQUIRED_FLAGS.txt
|
|
|
|
.. include:: /module/CMAKE_REQUIRED_DEFINITIONS.txt
|
|
|
|
.. include:: /module/CMAKE_REQUIRED_INCLUDES.txt
|
|
|
|
.. include:: /module/CMAKE_REQUIRED_LINK_OPTIONS.txt
|
|
|
|
.. include:: /module/CMAKE_REQUIRED_LIBRARIES.txt
|
|
|
|
.. include:: /module/CMAKE_REQUIRED_LINK_DIRECTORIES.txt
|
|
|
|
.. include:: /module/CMAKE_REQUIRED_QUIET.txt
|
|
|
|
.. note::
|
|
|
|
Prefer using :module:`CheckSymbolExists` or :module:`CheckSourceCompiles`
|
|
instead of this module, for the following reasons:
|
|
|
|
* ``check_function_exists()`` can't detect functions that are inlined
|
|
in headers or specified as a macro.
|
|
|
|
* ``check_function_exists()`` can't detect anything in the 32-bit
|
|
versions of the Win32 API, because of a mismatch in calling conventions.
|
|
|
|
* ``check_function_exists()`` only verifies linking, it does not verify
|
|
that the function is declared in system headers.
|
|
#]=======================================================================]
|
|
|
|
include_guard(GLOBAL)
|
|
|
|
macro(CHECK_FUNCTION_EXISTS FUNCTION VARIABLE)
|
|
if(NOT DEFINED "${VARIABLE}" OR "x${${VARIABLE}}" STREQUAL "x${VARIABLE}")
|
|
set(MACRO_CHECK_FUNCTION_DEFINITIONS
|
|
"-DCHECK_FUNCTION_EXISTS=${FUNCTION} ${CMAKE_REQUIRED_FLAGS}")
|
|
if(NOT CMAKE_REQUIRED_QUIET)
|
|
message(CHECK_START "Looking for ${FUNCTION}")
|
|
endif()
|
|
if(CMAKE_REQUIRED_LINK_OPTIONS)
|
|
set(CHECK_FUNCTION_EXISTS_ADD_LINK_OPTIONS
|
|
LINK_OPTIONS ${CMAKE_REQUIRED_LINK_OPTIONS})
|
|
else()
|
|
set(CHECK_FUNCTION_EXISTS_ADD_LINK_OPTIONS)
|
|
endif()
|
|
if(CMAKE_REQUIRED_LIBRARIES)
|
|
set(CHECK_FUNCTION_EXISTS_ADD_LIBRARIES
|
|
LINK_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
|
|
else()
|
|
set(CHECK_FUNCTION_EXISTS_ADD_LIBRARIES)
|
|
endif()
|
|
if(CMAKE_REQUIRED_LINK_DIRECTORIES)
|
|
set(_CFE_LINK_DIRECTORIES
|
|
"-DLINK_DIRECTORIES:STRING=${CMAKE_REQUIRED_LINK_DIRECTORIES}")
|
|
else()
|
|
set(_CFE_LINK_DIRECTORIES)
|
|
endif()
|
|
if(CMAKE_REQUIRED_INCLUDES)
|
|
set(CHECK_FUNCTION_EXISTS_ADD_INCLUDES
|
|
"-DINCLUDE_DIRECTORIES:STRING=${CMAKE_REQUIRED_INCLUDES}")
|
|
else()
|
|
set(CHECK_FUNCTION_EXISTS_ADD_INCLUDES)
|
|
endif()
|
|
|
|
if(CMAKE_C_COMPILER_LOADED)
|
|
set(_cfe_source CheckFunctionExists.c)
|
|
elseif(CMAKE_CXX_COMPILER_LOADED)
|
|
set(_cfe_source CheckFunctionExists.cxx)
|
|
else()
|
|
message(FATAL_ERROR "CHECK_FUNCTION_EXISTS needs either C or CXX language enabled")
|
|
endif()
|
|
|
|
try_compile(${VARIABLE}
|
|
SOURCE_FROM_FILE "${_cfe_source}" "${CMAKE_ROOT}/Modules/CheckFunctionExists.c"
|
|
COMPILE_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS}
|
|
${CHECK_FUNCTION_EXISTS_ADD_LINK_OPTIONS}
|
|
${CHECK_FUNCTION_EXISTS_ADD_LIBRARIES}
|
|
CMAKE_FLAGS -DCOMPILE_DEFINITIONS:STRING=${MACRO_CHECK_FUNCTION_DEFINITIONS}
|
|
"${CHECK_FUNCTION_EXISTS_ADD_INCLUDES}"
|
|
"${_CFE_LINK_DIRECTORIES}"
|
|
)
|
|
unset(_cfe_source)
|
|
unset(_CFE_LINK_DIRECTORIES)
|
|
|
|
if(${VARIABLE})
|
|
set(${VARIABLE} 1 CACHE INTERNAL "Have function ${FUNCTION}")
|
|
if(NOT CMAKE_REQUIRED_QUIET)
|
|
message(CHECK_PASS "found")
|
|
endif()
|
|
else()
|
|
if(NOT CMAKE_REQUIRED_QUIET)
|
|
message(CHECK_FAIL "not found")
|
|
endif()
|
|
set(${VARIABLE} "" CACHE INTERNAL "Have function ${FUNCTION}")
|
|
endif()
|
|
endif()
|
|
endmacro()
|