Thread: recvfrom() timeout

I found an example I like better than the one In the link I posted:

Code:

SOCKET     theSocket;
struct timeval stTimeOut;

fd_set stReadFDS;
fd_set stExcepFDS;
fd_set stWriteFDS;

FD_ZERO(&stReadFDS);
FD_ZERO(&stExcepFDS);
FD_ZERO(&stWriteFDS);

// Timeout of one second
stTimeOut.tv_sec = 1;
stTimeOut.tv_usec = 0;

     FD_SET(theSocket, &stReadFDS);
     FD_SET(theSocket, &stExcepFDS);
     FD_SET(theSocket, &stWriteFDS);

          int test = 0;
          char szBuf[256];
          memset(szBuf, ' ', sizeof(szBuf));

          while (true) {
               int t = select(-1, &stReadFDS, &stWriteFDS, &stExcepFDS, &stTimeOut);
               if (t = SOCKET_ERROR) {
                    fprintf(stderr, "Call to select() failed");
                    exit(1);
               }
               if (t != 0) {
                    printf("Something to do...");
                    if (FD_ISSET (theSocket, &stExcepFDS)) {
                         printf("Exception flag is set");// Deal with this
                    }
                    if (FD_ISSET(theSocket, &stReadFDS)) {
                         printf("There is data pending to be read..."); // Read data with recv()
                    }
                    if (FD_ISSET(theSocket, &stWriteFDS)) {
                         printf("There is data pending to be written...");// Send Data with send()

                    }
               }
               else {
                    printf("t is zero");
                    exit(1);
               }
          }

For what you are looking for, you only care about reading.

Change the select line to:
select(-1, &stReadFDS, 0, 0, &stTimeOut);

Then if select returns a number greater than 0, there is data to be read from the socket. If select returns 0, there was nothing to read and the call timed out.

Read the MSDN docs:
http://msdn.microsoft.com/library/de...k/select_2.asp

In winsock, that parameter is ignored. Since the poster didnt specify a platform, I assumed windows (as is evident by the SOCKET structure in my example).

You dont need to check for writefds. Read my last post

For what you are looking for, you only care about reading.
Change the select line to:

Code:

select(-1, &stReadFDS, 0, 0, &stTimeOut);

Well keep in mind that select() works on more than just sockets. It can also work on regular file descriptors as well.