Question

Im designing a multi cleint web server using multithreads in C using Pthreads, i have a Masterthread that is in a loop doing the listening, when there is a connection it spawns a new thread doing a function to serve, while the Masterthread continue listening for connection.

as i have notice from debuging, its serving only one connection at a time, the Accept() system call is waiting for that connection to close, then it will spawn the next connection in the queue.

Its acting like if its a single-thread web server.

    void *ServeThread(void *param)
{    int tsk;
     tsk = (int)param;

    /* here im serving the connection (tsk), and then close it */
}

void *MakeThreadPool(void *param)
{

    for(;;) {
        length = sizeof(cli_addr);
        if((socketfd = accept(listenfd, (struct sockaddr *)&cli_addr, &length)) < 0) { 
            exit(1);
                                                  }
    temps=socketfd;
    rc = pthread_create(&Thread[i++],NULL,ServeThread,(void *)temps);

                        }
}

How can i make accpet() contine listening al spawning theads when ever there is a connection without waiting for the previous one to finish ?

Answer 1

You observation is not correct, accept(2) does not wait for established TCP connection to complete. What you see is probably thread dispatch artifact – the main thread is preempted by the newly spawned thread and does not get to run until that one completes.

In general, thread-per-connection is a workable strategy, but you might want to create a pool of threads before accepting connection, instead of starting a new one every time.