pub type PFNGLPROGRAMUNIFORMUI64NVPROC = Option<unsafe extern "C" fn(program: GLuint, location: GLint, value: GLuint64EXT)>;
enum PFNGLPROGRAMUNIFORMUI64NVPROC { None, Some(unsafe extern "C" fn(_: u32, _: i32, _: u64)), }
No value.
Some value of type T.
T