> > There's still the problem of sending to multiple destinations: OK sendmmsg() can send multiple datagrams, but for a given socket.
> Hmm? sendmsg takes the destination address in the `struct msghdr` structure, and sendmmsg takes an array of those structures.
But that's still pointless on a connected socket. And if you're not using connected sockets, you're performing destination lookups for each and every datagram you're trying to send. It also means you're running with small buffers by default (the 212kB default buffers per socket are shared with all your destinations, no longer per destination). Thus normally you want to use connected socket when dealing with UDP in environments having performance requirements.
> Hmm? sendmsg takes the destination address in the `struct msghdr` structure, and sendmmsg takes an array of those structures.
But that's still pointless on a connected socket. And if you're not using connected sockets, you're performing destination lookups for each and every datagram you're trying to send. It also means you're running with small buffers by default (the 212kB default buffers per socket are shared with all your destinations, no longer per destination). Thus normally you want to use connected socket when dealing with UDP in environments having performance requirements.