pub type PFNGLUNIFORM4IPROC = Option<unsafe extern "C" fn(location: GLint, v0: GLint, v1: GLint, v2: GLint, v3: GLint)>;
enum PFNGLUNIFORM4IPROC { None, Some(unsafe extern "C" fn(_: i32, _: i32, _: i32, _: i32, _: i32)), }
No value.
Some value of type T.
T