Can you get two packets in one socket recv call for multicast?

Question

Self explanatory question. Can we get multiple UDP packets in one socket recv call when using Multicast?

Answer 1

When using recvfrom or recv on a UDP socket, you will only ever receive one complete packet at a time.

This applies to both unicast and multicast packets.

Answer 2

The recvmmsg() system call is an extension of recvmsg(2) that allows the caller to receive multiple messages from a socket using a single system call. (This has performance benefits for some applications.) A further extension over recvmsg(2) is support for a timeout on the receive operation.