summaryrefslogtreecommitdiff
path: root/Modules/CheckCSourceCompiles.cmake
blob: 67fc993be332316c654345cd2dfb18173b15795f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
# file Copyright.txt or https://cmake.org/licensing for details.

#[=======================================================================[.rst:
CheckCSourceCompiles
--------------------

Check if given C source compiles and links into an executable.

.. command:: check_c_source_compiles

  .. code-block:: cmake

    check_c_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_c_source_compiles()``:

  ``CMAKE_REQUIRED_FLAGS``
    Additional flags to pass to the compiler. Note that the contents of
    :variable:`CMAKE_C_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_C_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_C_SOURCE_COMPILES_ADD_LINK_OPTIONS
        LINK_OPTIONS ${CMAKE_REQUIRED_LINK_OPTIONS})
    else()
      set(CHECK_C_SOURCE_COMPILES_ADD_LINK_OPTIONS)
    endif()
    if(CMAKE_REQUIRED_LIBRARIES)
      set(CHECK_C_SOURCE_COMPILES_ADD_LIBRARIES
        LINK_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
    else()
      set(CHECK_C_SOURCE_COMPILES_ADD_LIBRARIES)
    endif()
    if(CMAKE_REQUIRED_INCLUDES)
      set(CHECK_C_SOURCE_COMPILES_ADD_INCLUDES
        "-DINCLUDE_DIRECTORIES:STRING=${CMAKE_REQUIRED_INCLUDES}")
    else()
      set(CHECK_C_SOURCE_COMPILES_ADD_INCLUDES)
    endif()
    file(WRITE "${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/src.c"
      "${SOURCE}\n")

    if(NOT CMAKE_REQUIRED_QUIET)
      message(CHECK_START "Performing Test ${VAR}")
    endif()
    try_compile(${VAR}
      ${CMAKE_BINARY_DIR}
      ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/src.c
      COMPILE_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS}
      ${CHECK_C_SOURCE_COMPILES_ADD_LINK_OPTIONS}
      ${CHECK_C_SOURCE_COMPILES_ADD_LIBRARIES}
      CMAKE_FLAGS -DCOMPILE_DEFINITIONS:STRING=${MACRO_CHECK_FUNCTION_DEFINITIONS}
      "${CHECK_C_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(CHECK_PASS "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${SOURCE}\n")
    else()
      if(NOT CMAKE_REQUIRED_QUIET)
        message(CHECK_FAIL "Failed")
      endif()
      set(${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()