Hello, I've made the attached patch to prevent the situation where the udp-receiver hang out indefinitly waiting for data when the server has been killed after having started to send data. In this case, the udp-received program would hang indefinitly. Since in my program, udp-receiver is called through system(...); the result is a hang. With this patch I use a SIGALARM signal to reset a flag to 0, and act as a watchdog. The watchdog is started just before the sending data phase of the protocol, and is feed each time a packet is received from the server. If 2 times in a row the watchdog is not feed, the program exit in error. The current value is set as a #define as 60s, which is in effect 2mn before udp-receiver is actually killed. However I am aware that this implementation is somehow crude, and I would be interested by any other way to do that. Additionally, if someone is interested by this patch, I could make it so that the watchdog period is configurable on the command-line. Thanks for your time, Julien -- People in the embedded space don't do prototypes. They hack something until it works, then it's done. --- Always code as if the person who will maintain your code is a maniac serial killer that knows where you live