# This version uses subs instead of classes.
use strict;
use warnings;

my $pid1 = fork();

if ($pid1) # parent #1
{
	my $pid2 = fork();

	if ($pid2) # parent #2
	{
		# This is just to illustrate that waitpid($pid1) works in parent #2

		# Wait for child #2 to finish so we're not interfering with its waitpid() call.
		waitpid($pid2, 0);

		my $waitpid1 = waitpid($pid1, 0);
		print "waitpid1 (in parent #2) = '$waitpid1'\n";
	}
	elsif ($pid2 == 0) # child #2
	{
		print "I'm child #2\n";

		#******* waitpid($pid1) inside child #2 will return -1.
		#******* It seems to not know about $pid1.  How can I make it work?
		my $waitpid1 = waitpid($pid1, 0);
		print "waitpid1 (in child #2) = '$waitpid1'\n";
	}
}
elsif ($pid1 == 0) # child #1
{
	print "I'm child #1\n";
}