Network Programming with Perl

UDP Errors

UDP errors are a little unusual because they can occur asynchronously. Consider what happens when you use send() to transmit a UDP datagram to aremote host that has no program listening on the specified port. With TCP, you would get a "connection refused" (ECONNREFUSED) error on the call to connect(). Similarly, a problem at the remote end, such as the server going down, will be reported synchronously the next time you read or write to the socket.

UDP is different. The return value from send() tells you nothing about whether the message was delivered at the remote end, because send() simply returns true if the message is successfully queued by the operating system. In the event that no server is listening at the other end and you ...