#!/usr/bin/perl
use strict;
use warnings;
use IPC::Open3;

# uncomment to handle SIGPIPE yourself
# $SIG{PIPE} = sub { warn "Broken pipe\n" };

open3(my $wh, my $rh, undef, qw'echo foo');

# tiny delay, so the command _has_ closed its stdin in the meantime
select undef,undef,undef, 0.2;

print $wh "foo\n";  # expected to fail in this case
close $wh;

print "done.\n";    # not reached, except when handling SIGPIPE yourself