pub type Dthash_f = Option<unsafe extern "C" fn(arg1: *mut Dt_t, arg2: *mut c_void, arg3: *mut Dtdisc_t) -> c_uint>;
pub enum Dthash_f { None, Some(unsafe extern "C" fn(*mut _dt_s, *mut c_void, *mut _dtdisc_s) -> u32), }
No value.
Some value of type T.
T