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