How to fork() and exec() in this one?

Question

I'm writing my own shell, but no fork gives my child_pid = 0... What's wrong there?

 while(true)
    {
        read_command(command);

        if ((child_pid = fork()) == -1)
        {
            fprintf(stderr, "can't fork\n");
            exit(1);
        }
        else if (child_pid == 0) //child
        {
            status=execl("./myShell" command);
        }
        else
        {
            wait(status); //parent
        }
    }

Answer 1

I guess that the (child_pid == -1) is not entered... Is the father ( else ) branch entered twice (by both process) or what?

Anyway I can't see a bug in that snippet of code. If you're sure your execution flow gets there, and has an unpredictable behavior its because of a bug.

I doubt glibc is bugged on your system: my best guess is that your program has got a broken pointer that broke everything. This is the most common cause of this kind of really weird behaviors.

Answer 2

Your code is OK. Add a debug print in if(child_pid == 0) and make sure it is not called. If fork cannot create a child, it sets errno to indicate the error occurred.