Is there any standard that says that udp packets must not be combined together by operating system?
In other words can I be sure that when I send small udp packets by sendto or analogues, I will receive udp packets of the same size by recvfrom, if I request length, which is far more than the size any of the sent packets?
Ok, I am sure that receving side cannot concatenate datagrams, because they may come reordered or be missed. But what is about sending side? Say I make several sendto to the same address, why OS should not concatenate data?