CheckFunctionExists

Check if a C function can be linked

check_function_exists
check_function_exists(<function> <variable>)

Checks that the <function> is provided by libraries on the system and store the result in a <variable>, which 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

a ;-list of macros to define (-DFOO=bar).

CMAKE_REQUIRED_INCLUDES

a ;-list of header search paths to pass to the compiler.

CMAKE_REQUIRED_LINK_OPTIONS

New in version 3.14: a ;-list of options to add to the link command.

CMAKE_REQUIRED_LIBRARIES

a ;-list of libraries to add to the link command. See policy CMP0075.

CMAKE_REQUIRED_QUIET

New in version 3.1: 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.