pub type PFNGLUNIFORM1FVARBPROC = Option<unsafe extern "C" fn(location: GLint, count: GLsizei, value: *const GLfloat)>;
enum PFNGLUNIFORM1FVARBPROC { None, Some(unsafe extern "C" fn(_: i32, _: i32, _: *const f32)), }
No value.
Some value of type T.
T