Pipelining Processes Post: 63117

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Top Forums Programming Pipelining Processes Post 63117 by Trivialnight on Tuesday 22nd of February 2005 07:54:07 PM

02-22-2005

Registered User

Well I did a little more testing on it and the problem seems to be that the parent process is not breaking out of the for loop like it is suppose to and not executing findfib() until the last process.

Code:

void doall(int id, int np)
{
   printf("ID: %d\n",id);
}

void mkpipeln(int *id, int np)
{  int fd[2]; pid_t child;
   for(*id = 1; *id < np; (*id)++){
      pipe(fd);
      child = fork();
      if(child > 0){
        dup2(fd[1],1);
        if((close(fd[0])<0)||(close(fd[1])<0)) die("close-1 failed");
        break;}
      else{
        printf("Parent: %d\n",(int)getppid());
        printf("Child: %d\n",(int)getpid());
        dup2(fd[0],0);
        if((close(fd[0])<0)||(close(fd[1])<0 )) die("close-1 failed");
        }
   }
}

Output for 7 processes if it helps at all:

Quote:

Parent: 6282
Child: 6283
Parent: 6283
Child: 6284
Parent: 6284
Child: 6285
Parent: 6285
Child: 6286
Parent: 6286
Child: 6287
Parent: 6287
Child: 6288
ID: 7

-tn

Trivialnight

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LEARN ABOUT PHP

pcntl_fork

PCNTL_FORK(3)								 1							     PCNTL_FORK(3)

pcntl_fork - Forks the currently running process

SYNOPSIS

       int pcntl_fork (void  )

DESCRIPTION

	The pcntl_fork(3) function creates a child process that differs from the parent process only in its PID and PPID. Please see your system's
       fork(2) man page for specific details as to how fork works on your system.

RETURN VALUES

	On success, the PID of the child process is returned in the parent's thread of execution, and a 0 is returned in  the  child's	thread	of
       execution. On failure, a -1 will be returned in the parent's context, no child process will be created, and a PHP error is raised.

EXAMPLES

       Example #1

	      pcntl_fork(3) example

	      <?php

	      $pid = pcntl_fork();
	      if ($pid == -1) {
		   die('could not fork');
	      } else if ($pid) {
		   // we are the parent
		   pcntl_wait($status); //Protect against Zombie children
	      } else {
		   // we are the child
	      }

	      ?>

SEE ALSO

       pcntl_waitpid(3), pcntl_signal(3), setproctitle(3).

PHP Documentation Group 													     PCNTL_FORK(3)

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