I experiment a little with the same idea, and I have something that might work :

#!perl

use Win32API::File qw(:Func :FILE_ :FILE_SHARE_);
sub FILE_FLAG_BACKUP_SEMANTICS () { 0x0200_0000 }
sub FSCTL_GET_RETRIEVAL_POINTERS () { 0x90073 }

my $f = $0;
$f =~ s,/,\\,go;

# CreateFile->Call
#    FH, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANT
+ICS, NULL;

  my $fh= createFile( "$f", {
        Access => 'r',
        Share => FILE_SHARE_READ,
        Create => 'e',
        #Attributes=>"hst",
        Flags=>FILE_FLAG_BACKUP_SEMANTICS()
        } ) or  die "Can't create file, $0: $^E\n";
  

  my $vcn = 0 ; # virtual cluster number ...

  my $inBuf = pack ('L2',$vcn,0); # LARGE: Quad hence L2 !!! ;
  my $outBuf = pack ('L8',0); # ExCount,StartVCN,NextVCN,LCN
  my $dwByteReturned = 0; # DWORD;

  printf "Control code: %x\n",FSCTL_GET_RETRIEVAL_POINTERS;
  DeviceIoControl($fh,
    FSCTL_GET_RETRIEVAL_POINTERS,
    $inBuf,length($inBuf),
    $outBuf,length($outBuf),
    $dwBytesReturned,
    []);
  my $error = Win32::GetLastError();
  print "error-no: $error\n";
  warn "DeviceIoControl->Call: ", Win32::FormatMessage($error) if ($er
+ror);
  printf "BytesReturned: %u\n",$dwBytesReturned;
  printf "outBuf %s\n",unpack 'H*',substr($outBuf,0,80);


1;
[download]

Let me know if it works for you ?
+Michel

You can simplify your error handling. This:

  DeviceIoControl($fh,
    FSCTL_GET_RETRIEVAL_POINTERS,
    $inBuf,length($inBuf),
    $outBuf,length($outBuf),
    $dwBytesReturned,
    []);
 my $error = Win32::GetLastError();
  print "error-no: $error\n";
  warn "DeviceIoControl->Call: ", Win32::FormatMessage($error) if ($er
+ror);
[download]

can be replaced by:

DeviceIoControl($fh,
    FSCTL_GET_RETRIEVAL_POINTERS,
    $inBuf,length($inBuf),
    $outBuf,length($outBuf),
    $dwBytesReturned,
    []
) or warn sprintf "DeviceIOControl failed with (%d) '%s'\n", $^E, $^E;
[download]

---

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In the absence of evidence, opinion is indistinguishable from prejudice.

RIP PCW It is as I've been saying!(Audio until 20090817)

Wow, 3 years later reply.. Anyway, I tried this and I get:

Control code: 90073
error-no: 0
BytesReturned: 32
outBuf 01000000000000000000000000000000010000000000000071d803000000000
+0
[download]

So, seems to be working.. but I have no idea where to go from here...