How do I check if there is data on the queue (Sockets)?
Author
Im using sockets in my game, and I have a TCP socket and a UDP socket. Is there any way of checking to see if there is any incoming data before I call recv() or recvfrom(), which would both block.
Or am I going to have to fire off another thread and block?
You could use ioctl() to find out how much data you can read:
unsigned long size = 0; int status = 0; status = ioctl(sock, FIONREAD, &size); // Win32 uses ioctlsocket() if (!status && size) do_whatever();[/source]or use select() with a timeout of zero:[source] fd_set readfds; struct timeval timeout; FD_ZERO(&readfds); FD_SET(sock, &readfds); timeout.tv_sec = 0; timeout.tv_usec = 0; select(sock+1, &readfds, NULL, NULL, &timeout); if (FD_ISSET(sock, &readfds)) do_whatever();[/source]or set your sockets to non-blocking:[source] unsigned long val = 1; ioctl(sock, FIONBIO, &val); // Win32 uses ioctlsocket
You could also use non-blocking sockets and just do the recv, testing to see if the socket would have blocked or not. Look at the FIONBIO option to ioctl (or ioctlsocket for Winsock)
-Mike
-Mike
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