pub type bign_deep_i = Option<unsafe extern "C" fn(n: usize, f_deep: usize, ec_d: usize, ec_deep: usize) -> usize>;
pub enum bign_deep_i { None, Some(unsafe extern "C" fn(usize, usize, usize, usize) -> usize), }
No value.
Some value of type T.
T