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GO Classes DPP | GATE CS | Operating System | Fork System Call

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5 5 votes

Consider the following C program. Assume that every $\texttt{fork()}$ call succeeds.

int main(void) {
    unsigned long int i;

    for (i = 0; i < 6; i++)
        if (fork() >= 0)
            continue;
        else
            break;
}

What is the total number of processes present after the loop terminates, including the original process?

  1. $7$
     
  2. $8$
     
  3. $32$
     
  4. $64$

2 Answers

0 0 votes

Asuccessful $\texttt{fork()}$ returns:

  • A positive value in the parent process
     
  • $0$ in the child process
     

Therefore, the condition $\texttt{fork() >= 0}$ is true in both the parent and the child. 

Every process continues to the next iteration.

The number of processes doubles in each iteration:

  • After iteration $1:~2$
  • After iteration $2: ~4$
  • After iteration $3: ~8$
  • After iteration $4: ~16$
  • After iteration $5: ~32$
  • After iteration $6: ~64$

Thus, the total number of processes is $2^6=64$.

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