check_nonce

Check nonce validity in a request and response. Return value reflects result: 1: nonces present and equal. 2: nonces both absent. 3: nonce present in response only. 0: nonces both present and not equal. -1: nonce in request only.

For most responders clients can check return > 0. If responder doesn’t handle nonces return != 0 may be necessary. return == 0 is always an error.