use feature qw( say );
use IPC::Open3 qw( open3 );

open(local *TO_CHLD, '<', '/dev/null') or die $!;
my $pid = open3(
   '<TO_CHLD',
   local *FR_CHLD,
   '>STDERR',
   'perl', '-E', 'sleep 2; say $$;'
);
say time, ": ", $pid;
while (<FR_CHLD>) {
   print time, ": Perl said: $_";
}
waitpid($pid, 0);