The new process does remain a child of the parent process across exec, since the open(FROM_CHILD,'-|') does an implicit fork. Here's an example: 
#!/usr/bin/perl

use warnings;
use strict;

my $pid = open(F,"-|");
if (!defined($pid)) { die "fork error: $!\n"; }
if ($pid)
{
  # Parent
  print "PARENT: PID is $$\n";
  sleep(1000);
  print <F>;
  close(F);
}
else
{
  # Child
  exec("/bin/bash","-c", 'echo CHILD: PID is $$, PPID is $PPID >&2');
}

[download]

Below, notice that 20474 is the parent process, and its child 20476 is a zombie. 

freenet{swgsh}~ $ perl tmp/t3  &
[2] 20474
freenet{swgsh}~ $ PARENT: PID is 20474
CHILD: PID is 20476, PPID is 20474

freenet{swgsh}~ $ ps
  PID TTY          TIME CMD
12912 pts/0    00:00:00 bash
13286 pts/0    00:00:39 emacs
20474 pts/0    00:00:00 perl
20476 pts/0    00:00:00 bash <defunct>
20487 pts/0    00:00:00 ps

[download]

In reply to Re^2: Protection from zombies by sgifford
in thread Protection from zombies by nomis80

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