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