CODEWITHSUNDEEP
cfork
Shobhit
Shobhit

Reputation: 59

The no. of processes is exponential even when i am not using parent process

Even when i run the part of the code which outputs something only in the child process but the output is coming many times. like here i gave chunks=8 but the output is like 100+ times.

Here is the code:

#include<stdio.h>
#include<string.h>


int main(){

int chunks=8;

int proc[25];
for(int proc_iter=0;proc_iter<chunks;proc_iter++){
    proc[proc_iter]=fork();

    if(proc[proc_iter]==0){
    printf("I am getting called with i=%d",proc_iter);
    }
}
return 0;
}

Upvotes: 1

Views: 181

Answers (1)

dbush
dbush

Reputation: 224157

This issue here is that the child process is performing the same loop as the parent process, so it forks as well.

If you set chunks to 2 and add the following loop after the initial loop:

for (int i=0;i<chunks;i++){
    printf("pid %d, i=%d, proc[i]=%d\n",getpid(),i,proc[i]);
}

You'll get output that looks something like this:

I am getting called with i=0
pid 30955, i=0, proc[i]=30956
pid 30955, i=1, proc[i]=30958
pid 30957, i=0, proc[i]=0
pid 30957, i=1, proc[i]=0
pid 30956, i=0, proc[i]=0
pid 30956, i=1, proc[i]=30957
I am getting called with i=1
pid 30958, i=0, proc[i]=30956
pid 30958, i=1, proc[i]=0

On the first iteration of the loop, one new process is created. Then both processes separately iterate the loop a second time and each forks another child. All four processes then complete the loop.

If you don't want the child processes to loop as well, have the child call exit:

if (proc[proc_iter]==0) {
    printf("I am getting called with i=%d\n",proc_iter);
    exit(0);
}

Then the output will look something like this:

I am getting called with i=0
I am getting called with i=1
pid 31020, i=0, proc[i]=31021
pid 31020, i=1, proc[i]=31022

Upvotes: 2

Related Questions