incrementing number

Hi, im forking 3 times in a loop like this but the variable "count" does not increment, it stays on '1' and therefore this is an infinite loop, and this simple thing dont make sense to me, some extra eyes to help me plz?

I have checked so that the pointer adress is the correct one every loop.

Code:

---

void increase(int* x)
{
 *x += 1;
}


main()
{
 int pid, i, number = 0;


 for(i = 0 ; 0 < 3 ; i++)
 {
  pid = fork();


  if(pid == -1)
  {
  exit(0);
  }
  else if(pid == 0)
  {
  increment(&number);


  sleep(3);
  exit(0);
  }
  else
  {
  waitpid(-1, NULL, 0);


  if(number >= 3)
  {
  exit(0);
  }
 }
}
 sleep(5);
}

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Well, 0 will always be less than 3 in your for loop.

Code:

---

  pid = fork();
 
 
  if(pid == -1)
  {
  exit(0);
  }
  else if(pid == 0)
  {
  increment(&number);

---

Each new process gets a new copy of number to play with.
So as far as the parent is concerned, the number never really changes.

Thank you very much! I get it now, I made everything much more simple by just using the for loop and checking value of i because it increments :cool:

Is it normal that the child's group PID is the same as the parent PID?

Read this.

Quote:

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Originally Posted by std10093

Read this.

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I think you missed that I ask about GROUP PID :P thanks anyway bro, that was usefull information even if I didnt need it atm :)

No idea if this is what you want.

process group ID

Process Group Functions - The GNU C Library

Tim S.

Quote:

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Originally Posted by Gatsu

Is it normal that the child's group PID is the same as the parent PID?

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From The Linux kernel: Processes, 10.2 Process Groups:

Quote:

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Every process is member of a unique process group, identified by its process group ID. (When the process is created, it becomes a member of the process group of its parent.)

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Bye, Andreas

Quote:

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Originally Posted by Gatsu

I think you missed that I ask about GROUP PID :P thanks anyway bro, that was usefull information even if I didnt need it atm :)

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Yeah I missed that. Sorry :)