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# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
# file LICENSE.rst or https://cmake.org/licensing for details.
#[=======================================================================[.rst:
CheckIncludeFiles
-----------------
This module provides a command to check one or more C/C++ header files.
Load this module in a CMake project with:
.. code-block:: cmake
include(CheckIncludeFiles)
Commands
^^^^^^^^
This module provides the following command:
.. command:: check_include_files
Checks once whether one or more header files can be included together in
source code:
.. code-block:: cmake
check_include_files(<includes> <variable> [LANGUAGE <language>])
This command checks once whether the given ``<includes>`` list of header
files exist and can be included together in a C or C++ source file. The
result of the check is stored in an internal cache variable named
``<variable>``. Specify the ``<includes>`` argument as a
:ref:`semicolon-separated list <CMake Language Lists>` of header file
names.
If ``LANGUAGE`` is set, the specified compiler will be used to perform the
check. Acceptable values are ``C`` and ``CXX``. If not set, the C
compiler will be used if enabled. If the C compiler is not enabled, the
C++ compiler will be used if enabled.
.. rubric:: Variables Affecting the Check
The following variables may be set before calling this command to modify
the way the check is run:
.. include:: /module/include/CMAKE_REQUIRED_FLAGS.rst
.. include:: /module/include/CMAKE_REQUIRED_DEFINITIONS.rst
.. include:: /module/include/CMAKE_REQUIRED_INCLUDES.rst
.. include:: /module/include/CMAKE_REQUIRED_LINK_OPTIONS.rst
.. include:: /module/include/CMAKE_REQUIRED_LIBRARIES.rst
.. include:: /module/include/CMAKE_REQUIRED_LINK_DIRECTORIES.rst
.. include:: /module/include/CMAKE_REQUIRED_QUIET.rst
.. versionadded:: 3.12
The ``CMAKE_REQUIRED_LIBRARIES`` variable, if policy :policy:`CMP0075` is
set to ``NEW``.
Examples
^^^^^^^^
Checking one or more C headers and storing the check result in cache
variables:
.. code-block:: cmake
include(CheckIncludeFiles)
check_include_files(sys/socket.h HAVE_SYS_SOCKET_H)
if(HAVE_SYS_SOCKET_H)
# The <net/if.h> header on Darwin and BSD-like systems is not self-contained
# and also requires <sys/socket.h>
check_include_files("sys/socket.h;net/if.h" HAVE_NET_IF_H)
else()
check_include_files(net/if.h HAVE_NET_IF_H)
endif()
The ``LANGUAGE`` option can be used to specify which compiler to use. For
example, checking multiple ``C++`` headers, when both ``C`` and ``CXX``
languages are enabled in the project:
.. code-block:: cmake
include(CheckIncludeFiles)
check_include_files("header_1.hpp;header_2.hpp" HAVE_HEADERS LANGUAGE CXX)
See Also
^^^^^^^^
* The :module:`CheckIncludeFile` module to check for a single C header.
* The :module:`CheckIncludeFileCXX` module to check for a single C++ header.
#]=======================================================================]
include_guard(GLOBAL)
macro(CHECK_INCLUDE_FILES INCLUDE VARIABLE)
if(NOT DEFINED "${VARIABLE}")
set(_src_content "/* */\n")
if("x${ARGN}" STREQUAL "x")
if(CMAKE_C_COMPILER_LOADED)
set(_lang C)
elseif(CMAKE_CXX_COMPILER_LOADED)
set(_lang CXX)
else()
message(FATAL_ERROR "CHECK_INCLUDE_FILES needs either C or CXX language enabled.\n")
endif()
elseif("x${ARGN}" MATCHES "^xLANGUAGE;([a-zA-Z]+)$")
set(_lang "${CMAKE_MATCH_1}")
elseif("x${ARGN}" MATCHES "^xLANGUAGE$")
message(FATAL_ERROR "No languages listed for LANGUAGE option.\nSupported languages: C, CXX.\n")
else()
message(FATAL_ERROR "Unknown arguments:\n ${ARGN}\n")
endif()
string(MAKE_C_IDENTIFIER ${VARIABLE} _variable_escaped)
if(_lang STREQUAL "C")
set(src ${_variable_escaped}.c)
elseif(_lang STREQUAL "CXX")
set(src ${_variable_escaped}.cpp)
else()
message(FATAL_ERROR "Unknown language:\n ${_lang}\nSupported languages: C, CXX.\n")
endif()
if(CMAKE_REQUIRED_INCLUDES)
set(CHECK_INCLUDE_FILES_INCLUDE_DIRS "-DINCLUDE_DIRECTORIES=${CMAKE_REQUIRED_INCLUDES}")
else()
set(CHECK_INCLUDE_FILES_INCLUDE_DIRS)
endif()
set(CHECK_INCLUDE_FILES_CONTENT "/* */\n")
set(MACRO_CHECK_INCLUDE_FILES_FLAGS ${CMAKE_REQUIRED_FLAGS})
foreach(FILE ${INCLUDE})
string(APPEND _src_content
"#include <${FILE}>\n")
endforeach()
string(APPEND _src_content
"\n\nint main(void){return 0;}\n")
set(_INCLUDE ${INCLUDE}) # remove empty elements
if("${_INCLUDE}" MATCHES "^([^;]+);.+;([^;]+)$")
list(LENGTH _INCLUDE _INCLUDE_LEN)
set(_description "${_INCLUDE_LEN} include files ${CMAKE_MATCH_1}, ..., ${CMAKE_MATCH_2}")
elseif("${_INCLUDE}" MATCHES "^([^;]+);([^;]+)$")
set(_description "include files ${CMAKE_MATCH_1}, ${CMAKE_MATCH_2}")
else()
set(_description "include file ${_INCLUDE}")
endif()
set(_CIF_LINK_OPTIONS)
if(CMAKE_REQUIRED_LINK_OPTIONS)
set(_CIF_LINK_OPTIONS LINK_OPTIONS ${CMAKE_REQUIRED_LINK_OPTIONS})
endif()
set(_CIF_LINK_LIBRARIES "")
if(CMAKE_REQUIRED_LIBRARIES)
cmake_policy(GET CMP0075 _CIF_CMP0075
PARENT_SCOPE # undocumented, do not use outside of CMake
)
if("x${_CIF_CMP0075}x" STREQUAL "xNEWx")
set(_CIF_LINK_LIBRARIES LINK_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
elseif("x${_CIF_CMP0075}x" STREQUAL "xOLDx")
elseif(NOT _CIF_CMP0075_WARNED)
set(_CIF_CMP0075_WARNED 1)
message(AUTHOR_WARNING
"Policy CMP0075 is not set: Include file check macros honor CMAKE_REQUIRED_LIBRARIES. "
"Run \"cmake --help-policy CMP0075\" for policy details. "
"Use the cmake_policy command to set the policy and suppress this warning."
"\n"
"CMAKE_REQUIRED_LIBRARIES is set to:\n"
" ${CMAKE_REQUIRED_LIBRARIES}\n"
"For compatibility with CMake 3.11 and below this check is ignoring it."
)
endif()
unset(_CIF_CMP0075)
endif()
if(CMAKE_REQUIRED_LINK_DIRECTORIES)
set(_CIF_LINK_DIRECTORIES
"-DLINK_DIRECTORIES:STRING=${CMAKE_REQUIRED_LINK_DIRECTORIES}")
else()
set(_CIF_LINK_DIRECTORIES)
endif()
if(NOT CMAKE_REQUIRED_QUIET)
message(CHECK_START "Looking for ${_description}")
endif()
try_compile(${VARIABLE}
SOURCE_FROM_VAR "${src}" _src_content
COMPILE_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS}
${_CIF_LINK_OPTIONS}
${_CIF_LINK_LIBRARIES}
CMAKE_FLAGS
-DCOMPILE_DEFINITIONS:STRING=${MACRO_CHECK_INCLUDE_FILES_FLAGS}
"${CHECK_INCLUDE_FILES_INCLUDE_DIRS}"
"${_CIF_LINK_DIRECTORIES}"
)
unset(_CIF_LINK_OPTIONS)
unset(_CIF_LINK_LIBRARIES)
unset(_CIF_LINK_DIRECTORIES)
if(${VARIABLE})
if(NOT CMAKE_REQUIRED_QUIET)
message(CHECK_PASS "found")
endif()
set(${VARIABLE} 1 CACHE INTERNAL "Have include ${INCLUDE}")
else()
if(NOT CMAKE_REQUIRED_QUIET)
message(CHECK_FAIL "not found")
endif()
set(${VARIABLE} "" CACHE INTERNAL "Have includes ${INCLUDE}")
endif()
endif()
endmacro()
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