linux socket c : send data when socket close—SIGPIPE, Broken pipe
send(sock , message , strlen(message) , MSG_NOSIGNAL)
http://stackoverflow.com/questions/34128572/linux-socket-c-send-data-when-other-socket-close
http://stackoverflow.com/questions/108183/how-to-prevent-sigpipes-or-handle-them-properly
http://stackoverflow.com/questions/18935446/program-received-signal-sigpipe-broken-pipe
http://stackoverflow.com/questions/16039275/c-socket-recv-error-handling