pub type PFNGLPATHSTENCILFUNCNVPROC = Option<unsafe extern "C" fn(func: GLenum, ref_: GLint, mask: GLuint)>;
enum PFNGLPATHSTENCILFUNCNVPROC { None, Some(unsafe extern "C" fn(_: u32, _: i32, _: u32)), }
No value.
Some value of type T.
T