Cannot close/terminate child process in Netbeans

Question

ANSWER in this previous question: https://mcmap.net/q/25577/-how-to-make-child-process-die-after-parent-exits It was not checked and quiet down, so I missed it. Already asked to be posted here

I am playing around with an application that creates a socket connection on a child process.

Now my problem is that trying to test it, but every time I run the application Netbeans creates main(Build, Run) and main(Run) when I close by clicking the red square or bottom right main(run) X button. The process "terminate" but it stays there, and then at exiting IDE it says "Exiting the IDE will terminate..." main(run)"

This is my first time with fork (and c) so I suppose I am not terminating the child process when terminating the main process, but shouldn't i be able to terminate manually too? Or is there a way for me to have a socket connection that constantly listens without blocking the rest of the code?

(note connection is not correct, since it still has blocking)

connection()
...
connection() {
    int pid = fork();
if (pid < 0)
    {
        perror("ERROR on fork");
    exit(1);
    }
if (pid == 0)  
    {
    int sockfd, portno, n;
    struct sockaddr_in serv_addr;
    struct hostent *server;

    fd_set fds;
    struct timeval timeout;
    int rc;
    /* Set time limit. */
    timeout.tv_sec = 0;
    timeout.tv_usec = 10;
    char buffer[256];

    portno = 4444;
    sockfd = socket(AF_INET, SOCK_STREAM, 0);

    if (sockfd < 0) 
        error("ERROR opening socket");
    server = gethostbyname("Localhost");
    if (server == NULL) {
        fprintf(stderr,"ERROR, no such host\n");
        exit(0);
    }
    bzero((char *) &serv_addr, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    bcopy((char *)server->h_addr, 
         (char *)&serv_addr.sin_addr.s_addr,
         server->h_length);
    serv_addr.sin_port = htons(portno);
    if (connect(sockfd,(struct sockaddr *)&serv_addr,sizeof(serv_addr)) < 0) 
        error("ERROR connecting");
    while(1)    {
        /* Create a descriptor set containing our two sockets.  */
        FD_ZERO(&fds);
        FD_SET(sockfd, &fds);
        rc = select(sizeof(fds)*8, &fds, NULL, NULL, &timeout);
        if (rc==-1) {
            perror("select failed");
        }
        if (rc > 0) {
            bzero(buffer,256);
            fgets(buffer,255,stdin);
            n = write(sockfd,buffer,strlen(buffer));
            if (n < 0) 
                 error("ERROR writing to socket");
        }
        rc = select(sizeof(fds)*8, &fds, NULL, NULL, &timeout);
        if (rc==-1) {
            perror("select failed");
        }
        if (rc > 0) {
            bzero(buffer,256);
            n = read(sockfd,buffer,255);
            if (n < 0) 
                 error("ERROR reading from socket");
            printf("Client: Server send %s",buffer);
            useEvent(buffer);
        }
    }
}

Curfew

Hard to know without more code/details on how the child behaves. Anyway, if the child creates a connection and parent is closing, you need to notify the child about this and shut down it properly. – Pemberton

I added the full code of the child process, the idea is to have a connection that read "listens" to the port and when called can send a message. – Curfew

Ok, but please format the code. A good idea for readability is to move child code to a function. And as I said before: if child is listening into a socket and parent dies, you need to notify the child about this and shut it down or it will just keep running. – Pemberton

Moving the child to a function can easily be done, but how to notify the child when the parent is closed is what I don't know how. I am terminating the main process from outside//inside, is there a "onExit()" or something function? Java Gui have EXIT_ON_CLOSE – Curfew

This is C, you don't have such advanced features. You can however listen to signals from OS which indicate a process to shut down (e.g. SIG_TERM in Linux). Of course this won't work if the signal is, say, SIG_KILL. – Pemberton

You could intercept the kill-signals in the parent (which is relatively close to onExit()) and notify the child via a IPC mechanism of your choice. This might even be possible in both directions, since everyone knows the other ones pid. – Mantelletta

Thanks for your help guys, i found the answer pretty nice trick if you want to check it out. – Curfew

possible duplicate of How to make child process die after parent exits? – Manakin