pub type PFNGLSETMULTISAMPLEFVAMDPROC = Option<unsafe extern "C" fn(pname: GLenum, index: GLuint, val: *const GLfloat)>;
enum PFNGLSETMULTISAMPLEFVAMDPROC { None, Some(unsafe extern "C" fn(_: u32, _: u32, _: *const f32)), }
No value.
Some value of type T.
T