Yes, i know, this's outside of my territory

Leave me explain a bit more

I need open a file through the dll, so i do:

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

Win32::API::Struct->typedef( 'MYHANDLE', qw(
  LPCTSTR lpFileName;
  DWORD dwDesiredAccess;
  DWORD dwShareMode;
  LPSECURITY_ATTRIBUTES lpSecurityAttributes;
  DWORD dwCreationDisposition;
  DWORD dwFlagsAndAttributes;
  HANDLE hTemplateFile; 
));
  
my $handle = Win32::API::Struct->new( 'MYHANDLE' ); 

my $filename = './catalog.db';

my $dll = Win32::API->new(
      'db.dll', 'OpenBlockFile','PS'
) or die $!;

$dll->Call($filename, $handle) or die $!;
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But in this's case the dll fill the struct with the associate resource or making this, the struct never would be a handle?

Are you getting a HANDLE or a struct? You keep saying handle, but you keep using a struct.

What's the signature of the DLL function? Is it

void __stdcall OpenBlockFile(
    const char* szFileName,   /* Input  */
    HANDLE*     pHandle       /* Output */
)
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If so, you need something like

my $dll = Win32::API->new(
      'db.dll', 'OpenBlockFile', 'PP', 'V' )
   or die $^E;

my $packed_handle = pack('L', 0);
$dll->Call($filename, $packed_handle);
$handle = unpack('L', $packed_handle);
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