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