pub type PFNGLISPOINTINSTROKEPATHNVPROC = Option<unsafe extern "C" fn(path: GLuint, x: GLfloat, y: GLfloat) -> GLboolean>;
enum PFNGLISPOINTINSTROKEPATHNVPROC { None, Some(unsafe extern "C" fn(_: u32, _: f32, _: f32) -> u8), }
No value.
Some value of type T.
T