UDP Sockets

Detailed Description

UDP is datagram I/O on a single UdpSocket type, which sends and receives unicast, broadcast, and multicast datagrams. It is an IODevice: after a local bind or a send destination is set, read() and write() are the inherited device operations, blocking or asynchronous, except that each write() sends one datagram and each read() receives one datagram rather than a TCP-style byte stream.

Three operations set where datagrams go and where they come from. bind() sets the local endpoint that receives datagrams, connect() associates a remote peer so writes go to that peer and reads come from it, and setTarget() sets a send destination without associating the socket, which is the path broadcast and multicast sends use. A socket may bind and still set a target, which is how a receiver that also sends to a group is set up.

A socket joins a multicast group to receive that group's datagrams, which means bind first, then join. UdpSocketOptions enable broadcast and set the hop limit; those values configure an operation, but they do not open a socket.

Classes
class	UdpSocketOptions
	UDP socket bind and send options. More...
class	UdpSocket
	UDP datagram socket. More...