use strict;
use warnings;
use Win32::Process;
use Win32;
use Data::Dumper;

my $netstat_obj;
my $create_status = Win32::Process::Create(
        $netstat_obj,
        'C:/Windows/System32/netstat.exe', 'netstat -a -e -n -o -s -r'
+,
        0, DETACHED_PROCESS | CREATE_NO_WINDOW | CREATE_SUSPENDED,
        'C:/temp/' ) || die Win32::FormatMessage(Win32::GetLastError()
+);

print Data::Dumper->new(['1', $create_status, $netstat_obj], ['where__
+________', 'create_status', 'netstat_obj'])->Indent(1)->Sortkeys(1)->
+Useqq(1)->Deparse(1)->Dump();

my $NETSTAT_FH;
my $open_status = Win32::Process::Open(
        $NETSTAT_FH,
        $netstat_obj->GetProcessID(),
        0 ) || die Win32::FormatMessage(Win32::GetLastError());

print Data::Dumper->new(['2', $open_status, $NETSTAT_FH], ['where_____
+_____', 'open_status', 'NETSTAT_FH'])->Indent(1)->Sortkeys(1)->Useqq(
+1)->Deparse(1)->Dump();

$netstat_obj->Resume();
my $netstat_data = '';
{
  my $offset = 0;
  my $length = 1024;
  my $buffer = undef;
  while(my $bytes_read = $NETSTAT_FH->sysread($buffer, $length, $offse
+t)) {
    if(defined $bytes_read) {
      $netstat_data .= $buffer;
      $buffer = undef;
      last if($bytes_read == 0);
      $offset += $bytes_read;
    }
    else { die "ERROR: Could not read from NETSTAT_FH: $!  "; }
  }
}
$netstat_obj->Wait(2000);
my $netstat_exit;
$netstat_obj->GetExitCode($netstat_exit);

print Data::Dumper->new(['3', $netstat_obj, $NETSTAT_FH, $netstat_data
+], ['where__________', 'netstat_obj', 'NETSTAT_FH', 'netstat_data'])-
+>Indent(1)->Sortkeys(1)->Useqq(1)->Deparse(1)->Dump();
[download]

The results of running the above code:

C:\temp>perl.exe sandbox.pl
$where__________ = 1;
$create_status = 1;
$netstat_obj = bless( do{\(my $o = 1776208)}, 'Win32::Process' );
$where__________ = 2;
$open_status = 1;
$NETSTAT_FH = bless( do{\(my $o = 1777552)}, 'Win32::Process' );
Your vendor has not defined Win32::Process macro sysread, used at sand
+box.pl line 32. (Error was: 'Invalid argument')
at C:/xampp/perl/site/lib/Win32/Process.pm line 53.
[download]

What I am trying to do in the above code is:

1. create a new (detached and suspended) Windows process sans command window
2. open a filehandle to the newly created process for reading said process's STDOUT
3. read all of the data from the filehandle
4. and wait for netstat to exit, then find its exit code

As the above output demonstrates, I am stuck on #3 (and despite the CREATE_NO_WINDOW constant, a window is  still  being created :-/ ).

In place of the sysread, I have tried: read, getlines, and getline; all with the same error "Your vendor has not defined Win32::Process macro X, used at …", where X is one of the aforementioned methods.