unsigned long GetOpenFileSize(char* ss)
{
    DWORD fp=0;
    HANDLE a;

    a=CreateFile(ss, GENERIC_READ, 0, NULL,
                 OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0 );
    if (a!=INVALID_HANDLE_VALUE)
    {
        fp = GetFileSize(a, NULL);
        CloseHandle(a);
    }

    return fp;
}

use strict;

use constant GENERIC_READ => 0x80000000;
use constant OPEN_EXISTING => 3;
use constant FILE_ATTRIBUTE_NORMAL => 0x00000080;


use Win32::API;
use Win32::API::Struct;

Win32::API::Struct->typedef(SECURITY_ATTRIBUTES => qw{
  DWORD nLength
  LPVOID lpSecurityDescriptor
  BOOL bInheritHandle
});


Win32::API->Import('kernel32', 'HANDLE CreateFile(LPCTSTR lpFileName, DWORD dwDesiredAccess, DWORD dwShareMode, LPSECURITY_ATTRIBUTES lpSecurityAttributes, DWORD dwCreationDisposition, DWORD dwFlagsAndAttributes, HANDLE hTemplateFile)');

Win32::API->Import('kernel32', 'DWORD GetFileSize(HANDLE hFile, LPDWORD lpFileSizeHigh)');

Win32::API->Import('kernel32', 'BOOL CloseHandle(HANDLE hObject)');

sub GetOpenFileSizeWin
{
   my ($file) = @_;
   my $handle = 0;
   my $size = 0;

   $handle = CreateFile($file, GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);
   if($handle)
   {
      $size = GetFileSize($handle, 0);
      CloseHandle($handle);
   }
   return $size;
}

Can't locate object method "Pack" via package "Config" at (eval 1) line 2, <DATA> line 164 

$handle = CreateFile($file, GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);