CMake/Modules/CheckCXXSourceCompiles.cmake
2018-12-01 17:56:23 +01:00

147 lines
5.7 KiB
CMake

# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
# file Copyright.txt or https://cmake.org/licensing for details.
#[=======================================================================[.rst:
CheckCXXSourceCompiles
----------------------
Check if given C++ source compiles and links into an executable.
.. command:: check_cxx_source_compiles
.. code-block:: cmake
check_cxx_source_compiles(<code> <resultVar>
[FAIL_REGEX <regex1> [<regex2>...]])
Check that the source supplied in ``<code>`` can be compiled as a C++ source
file and linked as an executable (so it must contain at least a ``main()``
function). The result will be stored in the internal cache variable specified
by ``<resultVar>``, with a boolean true value for success and boolean false
for failure. If ``FAIL_REGEX`` is provided, then failure is determined by
checking if anything in the output matches any of the specified regular
expressions.
The underlying check is performed by the :command:`try_compile` command. The
compile and link commands can be influenced by setting any of the following
variables prior to calling ``check_cxx_source_compiles()``:
``CMAKE_REQUIRED_FLAGS``
Additional flags to pass to the compiler. Note that the contents of
:variable:`CMAKE_CXX_FLAGS <CMAKE_<LANG>_FLAGS>` and its associated
configuration-specific variable are automatically added to the compiler
command before the contents of ``CMAKE_REQUIRED_FLAGS``.
``CMAKE_REQUIRED_DEFINITIONS``
A :ref:`;-list <CMake Language Lists>` of compiler definitions of the form
``-DFOO`` or ``-DFOO=bar``. A definition for the name specified by
``<resultVar>`` will also be added automatically.
``CMAKE_REQUIRED_INCLUDES``
A :ref:`;-list <CMake Language Lists>` of header search paths to pass to
the compiler. These will be the only header search paths used by
``try_compile()``, i.e. the contents of the :prop_dir:`INCLUDE_DIRECTORIES`
directory property will be ignored.
``CMAKE_REQUIRED_LINK_OPTIONS``
A :ref:`;-list <CMake Language Lists>` of options to add to the link
command (see :command:`try_compile` for further details).
``CMAKE_REQUIRED_LIBRARIES``
A :ref:`;-list <CMake Language Lists>` of libraries to add to the link
command. These can be the name of system libraries or they can be
:ref:`Imported Targets <Imported Targets>` (see :command:`try_compile` for
further details).
``CMAKE_REQUIRED_QUIET``
If this variable evaluates to a boolean true value, all status messages
associated with the check will be suppressed.
The check is only performed once, with the result cached in the variable
named by ``<resultVar>``. Every subsequent CMake run will re-use this cached
value rather than performing the check again, even if the ``<code>`` changes.
In order to force the check to be re-evaluated, the variable named by
``<resultVar>`` must be manually removed from the cache.
#]=======================================================================]
include_guard(GLOBAL)
macro(CHECK_CXX_SOURCE_COMPILES SOURCE VAR)
if(NOT DEFINED "${VAR}")
set(_FAIL_REGEX)
set(_key)
foreach(arg ${ARGN})
if("${arg}" MATCHES "^(FAIL_REGEX)$")
set(_key "${arg}")
elseif(_key)
list(APPEND _${_key} "${arg}")
else()
message(FATAL_ERROR "Unknown argument:\n ${arg}\n")
endif()
endforeach()
set(MACRO_CHECK_FUNCTION_DEFINITIONS
"-D${VAR} ${CMAKE_REQUIRED_FLAGS}")
if(CMAKE_REQUIRED_LINK_OPTIONS)
set(CHECK_CXX_SOURCE_COMPILES_ADD_LINK_OPTIONS
LINK_OPTIONS ${CMAKE_REQUIRED_LINK_OPTIONS})
else()
set(CHECK_CXX_SOURCE_COMPILES_ADD_LINK_OPTIONS)
endif()
if(CMAKE_REQUIRED_LIBRARIES)
set(CHECK_CXX_SOURCE_COMPILES_ADD_LIBRARIES
LINK_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
else()
set(CHECK_CXX_SOURCE_COMPILES_ADD_LIBRARIES)
endif()
if(CMAKE_REQUIRED_INCLUDES)
set(CHECK_CXX_SOURCE_COMPILES_ADD_INCLUDES
"-DINCLUDE_DIRECTORIES:STRING=${CMAKE_REQUIRED_INCLUDES}")
else()
set(CHECK_CXX_SOURCE_COMPILES_ADD_INCLUDES)
endif()
file(WRITE "${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/src.cxx"
"${SOURCE}\n")
if(NOT CMAKE_REQUIRED_QUIET)
message(STATUS "Performing Test ${VAR}")
endif()
try_compile(${VAR}
${CMAKE_BINARY_DIR}
${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/src.cxx
COMPILE_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS}
${CHECK_CXX_SOURCE_COMPILES_ADD_LINK_OPTIONS}
${CHECK_CXX_SOURCE_COMPILES_ADD_LIBRARIES}
CMAKE_FLAGS -DCOMPILE_DEFINITIONS:STRING=${MACRO_CHECK_FUNCTION_DEFINITIONS}
"${CHECK_CXX_SOURCE_COMPILES_ADD_INCLUDES}"
OUTPUT_VARIABLE OUTPUT)
foreach(_regex ${_FAIL_REGEX})
if("${OUTPUT}" MATCHES "${_regex}")
set(${VAR} 0)
endif()
endforeach()
if(${VAR})
set(${VAR} 1 CACHE INTERNAL "Test ${VAR}")
if(NOT CMAKE_REQUIRED_QUIET)
message(STATUS "Performing Test ${VAR} - Success")
endif()
file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log
"Performing C++ SOURCE FILE Test ${VAR} succeeded with the following output:\n"
"${OUTPUT}\n"
"Source file was:\n${SOURCE}\n")
else()
if(NOT CMAKE_REQUIRED_QUIET)
message(STATUS "Performing Test ${VAR} - Failed")
endif()
set(${VAR} "" CACHE INTERNAL "Test ${VAR}")
file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log
"Performing C++ SOURCE FILE Test ${VAR} failed with the following output:\n"
"${OUTPUT}\n"
"Source file was:\n${SOURCE}\n")
endif()
endif()
endmacro()