Re:Debugging memory corruption: who the hell writes “2” into...
by spacechild1 on Sunday November 14, 2021 @11:10AM
(#29218030)
Or to put it another way: depending on the timeout value, select() can achieve blocking or non-blocking I/O on several sockets simultaneously. In both cases, the sockets themselves can be either blocking or non-blocking.
There is no practical difference between blocking on select() for multiple sockets or blocking on recv() for a single socket - in both cases the thread can't do anything else.
BTW, the sockets themselves don't even have to be non-blocking.
Also, I'd like to stress that the concepts or blocking/non-blocking I/O and synchronous/asynchronous I/O are really orthogonal. You can do synchronous networking with non-blocking sockets and vice versa.