Non Blocking Socket Blocked by fgets

Question

I'm testing things out and i made a non blocking socket but the "fgets" ruined my plans. How can i prevent fgets for blocking out my while loop showing below? A code that solves this would be greatly appreciated.

fcntl(clientSocket, F_SETFL, O_NONBLOCK);

while(1){

     fgets(buffer,sizeof(buffer),stdin);
     send(clientSocket,buffer,sizeof(buffer),0);

     recv(clientSocket,buffer,sizeof(buffer),0);
     printf("%s",buffer);

}

`fgets()` is blocking on `stdin`. This has nothing to do with your non-blocking socket whatsoever. Look into `select` and `poll`/`epoll`. — Jonathon Reinhart, May 29 '17 at 21:24
if fgets() didn't block, what do you plan to do next - i.e. if there was no inut from fgets, what do you want to send ? — nos, May 29 '17 at 21:25
i want to have an input, but without blocking upcoming messages from recv. Imagine something like a Chat service between client and Server — betelgeusee, May 29 '17 at 21:31
You can use two threads, one for `fgets` and `send`, the other one for `recv` and `printf` — David Ranieri, May 29 '17 at 22:19

score -1 · Answer 1 · answered May 29 '17 at 21:26

-1

It's not recommended, but if you want you can just do:

if (fcntl(0, F_SETFL, O_NONBLOCK) == -1) {
   perror("fcntl");
   exit(EXIT_FAILURE);
}

And you have a non blocking stdin.

Hint: better use select or poll for waiting ready file descriptor.

answered May 29 '17 at 21:26

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Non Blocking Socket Blocked by fgets

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