eval { 
	$pid = open3("<&STDIN", \*OUTPUT, \*OUTERR, 'perl return.pl') ;
	$val = waitpid(-1,0); # <--- added this line
};

...

print "---pid$n";     print $pid . $n;  # <--- prints pid
print "---val$n";     print $val . $n;  # <--- prints pid
print "---\$?$n";     print $? >>8, $n; # <--- prints exit val