CheckLanguage.cmake
# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
# file Copyright.txt or https://cmake.org/licensing for details.
#.rst:
# CheckLanguage
# -------------
#
# Check if a language can be enabled
#
# Usage:
#
# ::
#
# check_language(<lang>)
#
# where <lang> is a language that may be passed to enable_language()
# such as "Fortran". If CMAKE_<lang>_COMPILER is already defined the
# check does nothing. Otherwise it tries enabling the language in a
# test project. The result is cached in CMAKE_<lang>_COMPILER as the
# compiler that was found, or NOTFOUND if the language cannot be
# enabled.
#
# Example:
#
# ::
#
# check_language(Fortran)
# if(CMAKE_Fortran_COMPILER)
# enable_language(Fortran)
# else()
# message(STATUS "No Fortran support")
# endif()
include_guard(GLOBAL)
macro(check_language lang)
if(NOT DEFINED CMAKE_${lang}_COMPILER)
set(_desc "Looking for a ${lang} compiler")
message(STATUS ${_desc})
file(REMOVE_RECURSE ${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/Check${lang})
file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/Check${lang}/CMakeLists.txt"
"cmake_minimum_required(VERSION ${CMAKE_VERSION})
project(Check${lang} ${lang})
file(WRITE \"\${CMAKE_CURRENT_BINARY_DIR}/result.cmake\"
\"set(CMAKE_${lang}_COMPILER \\\"\${CMAKE_${lang}_COMPILER}\\\")\\n\"
)
")
if(CMAKE_GENERATOR_INSTANCE)
set(_D_CMAKE_GENERATOR_INSTANCE "-DCMAKE_GENERATOR_INSTANCE:INTERNAL=${CMAKE_GENERATOR_INSTANCE}")
else()
set(_D_CMAKE_GENERATOR_INSTANCE "")
endif()
execute_process(
WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/Check${lang}
COMMAND ${CMAKE_COMMAND} . -G ${CMAKE_GENERATOR}
-A "${CMAKE_GENERATOR_PLATFORM}"
-T "${CMAKE_GENERATOR_TOOLSET}"
${_D_CMAKE_GENERATOR_INSTANCE}
OUTPUT_VARIABLE output
ERROR_VARIABLE output
RESULT_VARIABLE result
)
include(${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/Check${lang}/result.cmake OPTIONAL)
if(CMAKE_${lang}_COMPILER AND "${result}" STREQUAL "0")
file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log
"${_desc} passed with the following output:\n"
"${output}\n")
else()
set(CMAKE_${lang}_COMPILER NOTFOUND)
file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log
"${_desc} failed with the following output:\n"
"${output}\n")
endif()
message(STATUS "${_desc} - ${CMAKE_${lang}_COMPILER}")
set(CMAKE_${lang}_COMPILER "${CMAKE_${lang}_COMPILER}" CACHE FILEPATH "${lang} compiler")
mark_as_advanced(CMAKE_${lang}_COMPILER)
endif()
endmacro()