I am working on udp server/client application. For finding out if any of the client is down, server sends a handshake message to the client. Then, the server waits for the response of client to send some data to assure that the client is active. For this the server blocks in call to recv_from() unless the client replies back, but if the client is down, the server blocks infinitely in call to recv_from. I want to implement such a functionality on my server so that it waits in call to recv_from for a specific time (say 2 secs). If no data received from the client within 2 seconds, the client is considered to be dead and recv_from returns. Is there any way to do it? I searched internet but found solutions like setting MSG_DONTWAIT flag that returns immediately when no data received, but in my case, I don't want recv_from to return immediately but wait for data for a specific duration of time, and when no data received for that specific duration, the recv_from function should retun. Any help is appreciated.