Added in version 3.19.
Check once if source code can be built for a given language.
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 ofCMAKE_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.