CheckSourceCompiles

Added in version 3.19.

Check once if source code can be built for a given language.

check_source_compiles

check_source_compiles(<lang> <code> <resultVar>
                      [FAIL_REGEX <regex1> [<regex2>...]]
                      [SRC_EXT <extension>])

Check once that the source supplied in <code> can be built for code language <lang>. 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 file extension that matches the requested language. The SRC_EXT option can be used to override this with .<extension> instead.

The C example checks if the compiler supports the noreturn attribute:

set(CMAKE_TRY_COMPILE_TARGET_TYPE "STATIC_LIBRARY")

check_source_compiles(C
"#if !__has_c_attribute(noreturn)
#error \"No noreturn attribute\"
#endif"
HAVE_NORETURN)

The Fortran example checks if the compiler supports the pure procedure attribute:

set(CMAKE_TRY_COMPILE_TARGET_TYPE "STATIC_LIBRARY")

check_source_compiles(Fortran
"pure subroutine foo()
end subroutine"
HAVE_PURE)

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.

See also check_source_runs() to run compiled source.

The compile and link commands can be influenced by setting any of the following variables prior to calling check_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.