1# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
2# file Copyright.txt or https://cmake.org/licensing for details.
3
4#[=======================================================================[.rst:
5CheckFortranSourceCompiles
6--------------------------
7
8.. versionadded:: 3.1
9
10Check if given Fortran source compiles and links into an executable.
11
12.. command:: check_fortran_source_compiles
13
14  .. code-block:: cmake
15
16    check_fortran_source_compiles(<code> <resultVar>
17        [FAIL_REGEX <regex>...]
18        [SRC_EXT <extension>]
19    )
20
21  Checks that the source supplied in ``<code>`` can be compiled as a Fortran
22  source file and linked as an executable. The ``<code>`` must be a Fortran program
23  containing at least an ``end`` statement--for example:
24
25  .. code-block:: cmake
26
27    check_fortran_source_compiles("character :: b; error stop b; end" F2018ESTOPOK SRC_EXT F90)
28
29  This command can help avoid costly build processes when a compiler lacks support
30  for a necessary feature, or a particular vendor library is not compatible with
31  the Fortran compiler version being used. This generate-time check may advise the
32  user of such before the main build process. See also the
33  :command:`check_fortran_source_runs` command to actually run the compiled code.
34
35  The result will be stored in the internal cache
36  variable ``<resultVar>``, with a boolean true value for success and boolean
37  false for failure.
38
39  If ``FAIL_REGEX`` is provided, then failure is determined by checking
40  if anything in the output matches any of the specified regular expressions.
41
42  By default, the test source file will be given a ``.F`` file extension. The
43  ``SRC_EXT`` option can be used to override this with ``.<extension>`` instead--
44  ``.F90`` is a typical choice.
45
46  The underlying check is performed by the :command:`try_compile` command. The
47  compile and link commands can be influenced by setting any of the following
48  variables prior to calling ``check_fortran_source_compiles()``:
49
50  ``CMAKE_REQUIRED_FLAGS``
51    Additional flags to pass to the compiler. Note that the contents of
52    :variable:`CMAKE_Fortran_FLAGS <CMAKE_<LANG>_FLAGS>` and its associated
53    configuration-specific variable are automatically added to the compiler
54    command before the contents of ``CMAKE_REQUIRED_FLAGS``.
55
56  ``CMAKE_REQUIRED_DEFINITIONS``
57    A :ref:`;-list <CMake Language Lists>` of compiler definitions of the form
58    ``-DFOO`` or ``-DFOO=bar``. A definition for the name specified by
59    ``<resultVar>`` will also be added automatically.
60
61  ``CMAKE_REQUIRED_INCLUDES``
62    A :ref:`;-list <CMake Language Lists>` of header search paths to pass to
63    the compiler. These will be the only header search paths used by
64    ``try_compile()``, i.e. the contents of the :prop_dir:`INCLUDE_DIRECTORIES`
65    directory property will be ignored.
66
67  ``CMAKE_REQUIRED_LINK_OPTIONS``
68    .. versionadded:: 3.14
69
70    A :ref:`;-list <CMake Language Lists>` of options to add to the link
71    command (see :command:`try_compile` for further details).
72
73  ``CMAKE_REQUIRED_LIBRARIES``
74    A :ref:`;-list <CMake Language Lists>` of libraries to add to the link
75    command. These can be the name of system libraries or they can be
76    :ref:`Imported Targets <Imported Targets>` (see :command:`try_compile` for
77    further details).
78
79  ``CMAKE_REQUIRED_QUIET``
80    If this variable evaluates to a boolean true value, all status messages
81    associated with the check will be suppressed.
82
83  The check is only performed once, with the result cached in the variable
84  named by ``<resultVar>``. Every subsequent CMake run will re-use this cached
85  value rather than performing the check again, even if the ``<code>`` changes.
86  In order to force the check to be re-evaluated, the variable named by
87  ``<resultVar>`` must be manually removed from the cache.
88
89#]=======================================================================]
90
91include_guard(GLOBAL)
92include(Internal/CheckSourceCompiles)
93
94macro(CHECK_Fortran_SOURCE_COMPILES SOURCE VAR)
95  # Pass the SRC_EXT we used by default historically.
96  # A user-provided SRC_EXT argument in ARGN will override ours.
97  cmake_check_source_compiles(Fortran "${SOURCE}" ${VAR} SRC_EXT "F" ${ARGN})
98endmacro()
99