# CheckSourceRuns

New in version 3.19.

Check if given source compiles and links into an executable and can subsequently be run.

check_source_runs

      check_source_runs(<lang> <code> <resultVar>
                        [SRC_EXT <extension>])

  Check that the source supplied in `<code>` can be compiled as a source file for the requested language, linked as an executable and then run. If the `<code>` could be built and run successfully, the internal cache variable specified by `<resultVar>` will be set to 1, otherwise it will be set to a value that evaluates to boolean false (e.g. an empty string or an error message).

  By default, the test source file will be given a file extension that matches the requested language. The `SRC_EXT` option can be used to override this with `.<extension>` instead.

  The `<code>` must contain a valid main program. For example:

      check_source_runs(C
      "#include <stdlib.h>
      #include <stdnoreturn.h>
      noreturn void f(){ exit(0); }
      int main(void) { f(); return 1; }"
      HAVE_NORETURN)

      check_source_runs(Fortran
      "program test
      real :: x[*]
      call co_sum(x)
      end program"
      HAVE_COARRAY)

  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.

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

> `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`

>   New 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_QUIET`

>   New in version 3.1.

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