Will this succeed in forking 10 times?

[mrpeed]

timeToFork = 10;

for(int i = 0; i < timesToFork; ++i) {
pid = fork();

if(pid == -1) {
perror("Failed to fork.");
exit();
}
}

After 10 times will I reside in the 10th process?

[ne555]

It generates 2^10 process, so it forks 2^10-1 times.

> After 10 times will I reside in the 10th process?
Yes, also in the 1st, the 2nd, the 3th, ... the 1024th

[thejman250]

- The for loop will run 9 times, given pid is never equal to -1.

- I don't understand what your (fork) function does, so i really can't say more than that.

[ne555]

$ man fork
The fork() function shall create a new process. The new process (child process) shall be an exact copy of the calling process (parent process) except (...)


@thejman250: in the first process, the loop will run `timeToFork' times, so 10

[mrpeed]

So in total will I have ten process or will each new process create a process as well? How can I end up with exactly ten processes?

[thejman250]

@thejman250: in the first process, the loop will run `timeToFork' times, so 10

- I'm pretty sure it's nine, unless the fork function affects "i" somehow.

- ++i is quite different from i++

[ne555]

> will each new process create a process as well?
Yep

> How can I end up with exactly ten processes?
¿you are creating for the heck of it?


> ++i is quite different from i++
As long as you don't use the returned value, they are equivalent.

[thejman250]

As long as you don't use the returned value, they are equivalent.

- They are not equivalent at all. one updates before the loop starts, and one after.

- They are completely different in this case, as "i" is being used in order to continue the for loop.

[modoran]

To spawn exactly 10 child processes, determine parent process PID and break the loop if you are in the child, like this:

timeToFork = 10;

int mypid = getpid();
for(int i = 0; i < timesToFork; ++i) {
if (getpid() != mypid)
    break; // we are the child, abort


pid = fork();

if(pid == -1) {
perror("Failed to fork.");
exit();
}
}

[ne555]

if `pid' is 0, then you are in the child.

@thejman250: http://cplusplus.com/doc/tutorial/control/

[mrpeed]

So I could say if(pid == 0) break?