pub type PFNGLPROGRAMUNIFORM1FPROC = Option<unsafe extern "C" fn(program: GLuint, location: GLint, x: GLfloat)>;
enum PFNGLPROGRAMUNIFORM1FPROC { None, Some(unsafe extern "C" fn(_: u32, _: i32, _: f32)), }
No value.
Some value of type T.
T