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