pub type PFNGLGETFLOATI_VEXTPROC = Option<unsafe extern "C" fn(pname: GLenum, index: GLuint, params: *mut GLfloat)>;
enum PFNGLGETFLOATI_VEXTPROC { None, Some(unsafe extern "C" fn(_: u32, _: u32, _: *mut f32)), }
No value.
Some value of type T.
T