pub type PFNGLDEPTHRANGEARRAYVPROC = Option<unsafe extern "C" fn(first: GLuint, count: GLsizei, v: *const GLclampd)>;
enum PFNGLDEPTHRANGEARRAYVPROC { None, Some(unsafe extern "C" fn(_: u32, _: i32, _: *const f64)), }
No value.
Some value of type T.
T