#!/usr/bin/perl -w

use strict;
use Gtk2 '-init';
use Gtk2::Helper;
use Data::Dumper;
use FileHandle;
use IPC::Open2;
use Win32API::File;
use Win32;
use Win32::API;

{
my $api;
die "PeekNamedPipe"
    if ! ($api= Win32::API->Import("kernel32", "
            BOOL PeekNamedPipe(
            HANDLE hNamedPipe,
            LPVOID lpBuffer,
            DWORD nBufferSize,
            LPDWORD lpBytesRead,
            LPDWORD lpTotalBytesAvail,
            LPDWORD lpBytesLeftThisMessage
        );"));
}

my $wfh = FileHandle->new();
my $rfh = FileHandle->new();
open2($rfh,$wfh,"C:\\Windows\\System32\\cmd.exe");
my $hnd = Win32API::File::FdGetOsFHandle($rfh->fileno()); #get Win32 k
+ernel handle from Perl land
if($hnd == Win32API::File::INVALID_HANDLE_VALUE()) {
    die "bad hnd";
}
my $tag = Gtk2::Helper->add_watch($rfh, 'in',\&preview_call);

my $window = Gtk2::Window->new();
$window->signal_connect("destroy",sub{Gtk2->main_quit();});
$window->set_size_request(300,300);

    my $hbox = Gtk2::HBox->new();
    $window->add($hbox);

        my $button = Gtk2::Button->new("A");
        $button->signal_connect('clicked'=>sub{
                add_job();
            });
        $hbox->pack_start($button,1,1,0);
        $button = Gtk2::Button->new("B");
        $button->signal_connect('clicked'=>sub{
                print "i do nothing\n";
            });
        $hbox->pack_start($button,1,1,0);

$window->show_all();
Gtk2->main();

sub preview_call {
    my $bRead = 0;
    my $bLeft = 0;
    my $bAvail = 0;
    my $ret = 0;
    my $buffer;
    $bAvail = "\x00" x 4;
    $ret = PeekNamedPipe($hnd,undef,0,undef,$bAvail,undef);
    if(!$ret) {
        my $err = Win32::GetLastError();
        die "PNP failed $err $^E";
    }
    $bAvail = unpack('L', $bAvail) . "\n";
    if($bAvail > 0) {
        print "Available: $bAvail\n";
        sysread($rfh,$buffer,$bAvail);
        print $buffer . "\n";
    }
    while (Gtk2->events_pending()) {Gtk2->main_iteration();}
    return 1;
}

sub add_job {
    print $wfh "dir\n\n";
}
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