# CheckFortranSourceCompiles

Added in version 3.1.

Check once if Fortran source code can be built.

check_fortran_source_compiles

      check_fortran_source_compiles(<code> <resultVar>
          [FAIL_REGEX <regex>...]
          [SRC_EXT <extension>]
      )

  Check once that the source supplied in `<code>` can be built. The result is stored in the internal cache variable specified by `<resultVar>`, with boolean `true` for success and boolean `false` for failure.

  If `FAIL_REGEX` is provided, then failure is determined by checking if anything in the compiler output matches any of the specified regular expressions.

  By default, the test source file will be given a `.F` file extension. The `SRC_EXT` option can be used to override this with `.<extension>` instead-- `.F90` is a typical choice.

  See also `check_source_compiles()` for a more general command syntax.

  See also `check_source_runs()` to run compiled source.

  Internally, `try_compile()` is used to compile the source. If `CMAKE_TRY_COMPILE_TARGET_TYPE` is set to `EXECUTABLE` (default), the source is compiled and linked as an executable program. If set to `STATIC_LIBRARY`, the source is compiled but not linked. In any case, all functions must be declared as usual.

  The compile and link commands can be influenced by setting any of the following variables prior to calling `check_fortran_source_compiles()`:

> `CMAKE_REQUIRED_FLAGS`

>   String of additional flags to pass to the compiler. The string must be space-delimited--a ;-list will not work. The contents of `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 ;-list 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 ;-list of header search paths to pass to the compiler. These will be the only header search paths used--the contents of the `INCLUDE_DIRECTORIES` directory property will be ignored.

> `CMAKE_REQUIRED_LINK_OPTIONS`

>   Added in version 3.14.

>   A ;-list of options to add to the link command (see `try_compile()` for further details).

> `CMAKE_REQUIRED_LIBRARIES`

>   A ;-list of libraries to add to the link command. These can be the name of system libraries or they can be Imported Targets (see `try_compile()` for further details).

> `CMAKE_REQUIRED_LINK_DIRECTORIES`

>   Added in version 3.31.

>   A ;-list of libraries search paths to pass to the linker (see `try_compile()` for further details).

> `CMAKE_REQUIRED_QUIET`

>   Added in version 3.1.

>   If this variable evaluates to a boolean true value, all status messages associated with the check will be suppressed.