pub type PFNGLUNIFORM3I64NVPROC = Option<unsafe extern "C" fn(_: i32, _: i64, _: i64, _: i64)>;
enum PFNGLUNIFORM3I64NVPROC { None, Some(unsafe extern "C" fn(_: i32, _: i64, _: i64, _: i64)), }
No value.
Some value of type T.
T