Linux: is there a read or recv from socket with timeout?
You can use the setsockopt function to set a timeout on receive operations:
SO_RCVTIMEO
Sets the timeout value that specifies the maximum amount of time an input function waits until it completes. It accepts a timeval structure with the number of seconds and microseconds specifying the limit on how long to wait for an input operation to complete. If a receive operation has blocked for this much time without receiving additional data, it shall return with a partial count or errno set to [EAGAIN] or [EWOULDBLOCK] if no data is received. The default for this option is zero, which indicates that a receive operation shall not time out. This option takes a timeval structure. Note that not all implementations allow this option to be set.
// LINUXstruct timeval tv;tv.tv_sec = timeout_in_seconds;tv.tv_usec = 0;setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO, (const char*)&tv, sizeof tv);// WINDOWSDWORD timeout = timeout_in_seconds * 1000;setsockopt(socket, SOL_SOCKET, SO_RCVTIMEO, (const char*)&timeout, sizeof timeout);// MAC OS X (identical to Linux)struct timeval tv;tv.tv_sec = timeout_in_seconds;tv.tv_usec = 0;setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO, (const char*)&tv, sizeof tv);
Reportedly on Windows this should be done before calling bind
. I have verified by experiment that it can be done either before or after bind
on Linux and OS X.
Here's some simple code to add a time out to your recv
function using poll
in C:
struct pollfd fd;int ret;fd.fd = mySocket; // your socket handler fd.events = POLLIN;ret = poll(&fd, 1, 1000); // 1 second for timeoutswitch (ret) { case -1: // Error break; case 0: // Timeout break; default: recv(mySocket,buf,sizeof(buf), 0); // get your data break;}