CODEWITHSUNDEEP
c
Pulpit
Pulpit

Reputation: 95

How to write a program that creates 2 parent processes and one child for each?

I'm not sure what does this code do.

#include <sys/wait.h>
#include <stdio.h>
#include <unistd.h>

int main(void)
{
    for(int i=0; i<2; i++)
    {
        int pid=fork();
        if(pid==0)
        {
            printf("child process \n");
            printf("Child pid id [%d], parent pid is [%d]\n", (int) getpid(), (int) getppid());
        } else if(pid>0)
        {
            int stats;
            wait(&stats);
            printf("parent process \n");
            printf("Child pid id [%d], parent pid is [%d]\n", (int) getpid(), (int) getppid());
        }
    }
    return 0;
}

I call fork() and assign it's value to variabe pid. Then we go to int stats, next line returns pid=0, then the program displays child process and then the parent process. It works pretty nice, but only when i<1. I thought that it is possible to do the same thing once again, but it's strange. fork() creates a new child process, so if it is used only once, if should create a child process, which parent is an IDE. Why am I wrong and what should I change to make 2 parents and 1 child for each, basically 4 processes?

Upvotes: 0

Views: 235

Answers (1)

Acorn
Acorn

Reputation: 26196

I am not completely sure what you mean by "2 parents". In any case, you need to return the child so that they do not loop again:

        printf("Child pid id [%d], parent pid is [%d]\n", (int) getpid(), (int) getppid());
        return 0;

Otherwise you will have the children spawning other processes.

Upvotes: 1

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