Multiprocessing and Pipes in C

Question

I\'m trying to learn how to work with fork() to create new processes and pipes to communicate with each process. Let\'s say I have a list that contains

Answer 1

The overall picture is usually:

pid_t pids[3];
int fd[3][2];

int i;
for (i = 0; i < 3; ++i) {
    /* create the pipe */
    if (pipe(fd[i]) < 0) {
            perror("pipe error");
            exit(1);
    }

   /* fork the child */
   pid[i] = fork();
   if (pid[i] < 0) {
       perror("fork error");
   } else if (pid[i] > 0) {
       /* in parent process */
       /* close reading end */
       close(fd[i][0]);
   } else {
       /* in child process */
       /* close writing end */
       close(fd[i][1]);
       /* read from parent */
       read(fd[i][0], line, max);
       ...
    }
}

/* in parent process */
char words[100][10] = {...};
int j, child = 0;
/* for all words */
for (j = 0; j < 100; ++j) {
    /* write to child */
    write(fd[child][1], words[j], strlen(words[j]));
    ...
    ++child;
    if (child >= 3)
        child = 0;
}

Duplicate the pipe part for communicating back from child to parent. Be careful not to deadlock when parent and child are trying to communicate in both directions simultaneously.