Why is there a setnonblocking function that is unused?

[JohnZ622]

I see setnonblocking function in net.c but it is invoked anywhere. A unfinished feature or dead code? It's not necessary to use non-blocking sockets here right?

[bmah888]

More like dead code. IIRC, we needed to use non-blocking sockets when iperf3 had a single-threaded design, in order to avoid hanging the main (and only) thread. That's not really a thing for the multi-threaded design used in iperf-3.16 and later.