CheckFunctionExists

Check if a C function can be linked:

check_function_exists(<function> <variable>)

Check that the <function> is provided by libraries on the system and store the result in a <variable>. <variable> will be created as an internal cache variable.

The following variables may be set before calling this macro to modify the way the check is run:

CMAKE_REQUIRED_FLAGS = string of compile command line flags
CMAKE_REQUIRED_DEFINITIONS = list of macros to define (-DFOO=bar)
CMAKE_REQUIRED_INCLUDES = list of include directories
CMAKE_REQUIRED_LIBRARIES = list of libraries to link
CMAKE_REQUIRED_QUIET = execute quietly without messages

Note

Prefer using CheckSymbolExists instead of this module, for the following reasons:

• check_function_exists() can’t detect functions that are inlined in headers or specified as a macro.

• check_function_exists() can’t detect anything in the 32-bit versions of the Win32 API, because of a mismatch in calling conventions.

• check_function_exists() only verifies linking, it does not verify that the function is declared in system headers.