Files
CMake/Modules/CheckFunctionExists.cmake
Matthew Woehlke db76876db5 Modules: Use new SOURCES_FROM_* try_compile (1/2)
Modify some modules that ship with CMake to use the new SOURCES_FROM_*
arguments to try_compile / try_run as added by commits cb14ae2b87
(try_compile: Add SOURCE_FROM_{ARG,VAR}, 2022-09-21) and 611d801790
(try_compile: Add SOURCE_FROM_FILE, 2022-09-22). This covers users which
previously either used an existing file (but sometimes needed to rename
it), or which wrote out their source in entirety. It does NOT cover
users that actually need configure_file functionality, as those will be
more involved to update and will thus be tackled in part 2.
2022-09-27 13:29:52 -04:00

120 lines
4.3 KiB
CMake

# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
# file Copyright.txt or https://cmake.org/licensing for details.
#[=======================================================================[.rst:
CheckFunctionExists
-------------------
Check if a C function can be linked
.. 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 a ``<variable>``, which will be created as an internal
cache variable.
The following variables may be set before calling this macro to modify the
way the check is run:
``CMAKE_REQUIRED_FLAGS``
string of compile command line flags.
``CMAKE_REQUIRED_DEFINITIONS``
a :ref:`;-list <CMake Language Lists>` of macros to define (-DFOO=bar).
``CMAKE_REQUIRED_INCLUDES``
a :ref:`;-list <CMake Language Lists>` of header search paths to pass to
the compiler.
``CMAKE_REQUIRED_LINK_OPTIONS``
.. versionadded:: 3.14
a :ref:`;-list <CMake Language Lists>` of options to add to the link command.
``CMAKE_REQUIRED_LIBRARIES``
a :ref:`;-list <CMake Language Lists>` of libraries to add to the link
command. See policy :policy:`CMP0075`.
``CMAKE_REQUIRED_QUIET``
.. versionadded:: 3.1
execute quietly without messages.
.. note::
Prefer using :Module:`CheckSymbolExists` 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 ${CMAKE_REQUIRED_LIBRARIES})
else()
set(CHECK_FUNCTION_EXISTS_ADD_LIBRARIES)
endif()
if(CMAKE_REQUIRED_INCLUDES)
set(CHECK_FUNCTION_EXISTS_ADD_INCLUDES
"-DINCLUDE_DIRECTORIES:STRING=${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}
"${CHECK_FUNCTION_EXISTS_ADD_INCLUDES}"
OUTPUT_VARIABLE OUTPUT)
unset(_cfe_source)
if(${VARIABLE})
set(${VARIABLE} 1 CACHE INTERNAL "Have function ${FUNCTION}")
if(NOT CMAKE_REQUIRED_QUIET)
message(CHECK_PASS "found")
endif()
file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log
"Determining if the function ${FUNCTION} exists passed with the following output:\n"
"${OUTPUT}\n\n")
else()
if(NOT CMAKE_REQUIRED_QUIET)
message(CHECK_FAIL "not found")
endif()
set(${VARIABLE} "" CACHE INTERNAL "Have function ${FUNCTION}")
file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log
"Determining if the function ${FUNCTION} exists failed with the following output:\n"
"${OUTPUT}\n\n")
endif()
endif()
endmacro()