pub type CK_NOTIFY = Option<unsafe extern "C" fn(arg1: CK_SESSION_HANDLE, arg2: CK_NOTIFICATION, arg3: *mut c_void) -> CK_RV>;
pub enum CK_NOTIFY { None, Some(unsafe extern "C" fn(u64, u64, *mut c_void) -> u64), }
No value.
Some value of type T.
T