pub type DD_HFP = Option<unsafe extern "C" fn(arg1: *mut DdManager, arg2: *const c_char, arg3: *mut c_void) -> c_int>;
pub enum DD_HFP { None, Some(unsafe extern "C" fn(*mut DdManager, *const i8, *mut c_void) -> i32), }
No value.
Some value of type T.
T