c fork's child ppid does not match parent's pid

Question

I'm totally new to C. I tried the following code, expecting that the child's ppid would match the parent's pid, but this is not the case.

int main() {


    int pid;

    printf("I'm process with pid=%d\n", getpid());

    switch (pid = fork()) {
        case -1:
            perror("fork");
            exit(1);
        case 0:
            printf("I'm the child process: pid=%d, ppid=%d\n", getpid(), getppid());
            break;
        default:
            printf("I'm the parent process: pid=%d, ppid=%d\n", getpid(), getppid());
            break;
    }

    exit(0);

}

> gcc -o fork fork.c 
> ./fork 
I'm process with pid=16907
I'm the parent process: pid=16907, ppid=6604
I'm the child process: pid=16908, ppid=1 // <-- expected ppid=16907, why 1?
>

What did I do wrong ?

Answer 1

It is likely the parent process has already exited and no longer exists. You could try some delay in the parent.

Answer 2

'init' which is the root process running in a linux system has pid 1 .

When a process's parent gets terminated before itself(i.e. the child) , the child becomes an 'orphan' process and is taken up by the root process or the process just above the hierarchy of the process which created it(parent process) .

Hence , here it is taken up by and executed under init which has pid = 1 . So, delay your parent process for solution.