pub type PFNGLMULTITEXCOORDP4UIPROC = Option<unsafe extern "C" fn(_: u32, _: u32, _: u32)>;
enum PFNGLMULTITEXCOORDP4UIPROC { None, Some(unsafe extern "C" fn(_: u32, _: u32, _: u32)), }
No value.
Some value of type T.
T