Linux Socket: How to detect disconnected network in a client program?

Question

I am debugging a c based linux socket program. As all the examples available in websites, I applied the following structure:

sockfd= socket(AF_INET, SOCK_STR         


        

Answer 1

Check the return value, and see if it's equal to this value:

EPIPE
This socket was connected but the connection is now broken. In this case, send generates a SIGPIPE signal first; if that signal is ignored or blocked, or if its handler returns, then send fails with EPIPE.

Also add a check for the SIGPIPE signal in your handler, to make it be more controllable.