CheckCCompilerFlag¶
Check whether the C compiler supports a given flag.
- check_c_compiler_flag¶
check_c_compiler_flag(<flag> <resultVar>)
Check that the
<flag>
is accepted by the compiler without a diagnostic. Stores the result in an internal cache entry named<resultVar>
.
A positive result from this check indicates only that the compiler did not issue a diagnostic message when given the flag. Whether the flag has any effect or even a specific one is beyond the scope of this module.
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_c_compiler_flag()
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
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.