my $pid = fork() // die "fork: $!";
if( $pid ){
	print "forked: i am shelling out\n";
	spawn();
	print "after shelling out.\n";
}
print "I am now waiting for background process.\n";
waitpid $pid, 0;
print "done.\n";

sub spawn {
	my $pid = open(my $xx, "sleep 1 2>&1|") or die "fork: $!";
	print "implicitly waiting for child...\n";
	# close($xx);
}

##</code><code>##

print "before spawn\n";
spawn();
print "after spawn\n";

sub spawn {
	my $pid = open(my $xx, "sleep 3 2>&1|") or die "fork: $!";
	print "implicitly waiting for child...\n";
	# the proper way to wait for the command to exit:
	# close($xx);
}

# output:

before spawn
implicitly waiting for child... # sleep...
after spawn