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Hello, I've been trying (for a few days) to use Win32::API and Win32::API::Prototype to import a couple of functions from a DLL, but I can't get it to work properly. I already got a function with no parameters to work, but the other takes a complex struct as a parameter, and I'm obviously missing something. I wonder if you monks can help me out here.

The DLL was written in Delphi ("DiscIdCalcDLL.dll", from http://webplaza.pt.lu/public/vigatol/discidcalc/), and the documentation says:

The GetCdRomDrives scans for Cd-Rom installed on the system and retrie
+ves informations over the Cd-Rom drive.
function GetCdRomDrives(var CdRoms: TCdRoms): Boolean;
Parameters
CdRoms
Return Values
If the function succeeds, the return value is TRUE.
If the function fails, the return value is FALSE.
[download]

The TCdRoms data type is defined as follows:

TCdRom = record
HaId : Byte;
Target : Byte;
Lun : Byte;
Vendor : ShortString;
ProductId : ShortString;
Revision : ShortString;
VendorSpec: ShortString;
end;

TCdRoms = record
CdRomCount: Byte;
CdRom : array[0..25] of TCdRom;
end;
[download]

So I did this in Perl:

#!/usr/bin/perl

use Win32::API::Prototype;

Win32::API::Struct->typedef( TCdRom => qw{
  int HaId;
  int Target;
  int Lun;
  char Vendor[256];
  char ProductId[256];
  char Revision[256];
  char VendorSpec[256];
});

Win32::API::Struct->typedef( TCdRoms => qw{
  BYTE CdRomCount;
  TCdRom Drive[26];
});

ApiLink( 'DiscIdCalcDLL.dll', 'int GetCdRomDrives(LPTCdRoms CdRoms)' )
+ || die;

$cds = Win32::API::Struct->new('TCdRoms');
for (my $i = 0; $i < 26; $i++)
  {
  $drvs[$i] = Win32::API::Struct->new('TCdRom');
  $cds->{Drive}[$i] = $drvs[$i];
  }

$x = GetCdRomDrives(\$cds);

########## (ETC) #########################
[download]

At this point, $x contains 1, and I'm not sure whether it means "true" or "false" (I would expect -1 for false, 0 for true). And $cds is empty. Using the perl debugger, I get this:

  DB<4> x $cds
0  Win32::API::Struct=HASH(0x1c3dc30)
   'Drive' => ARRAY(0x1c3e050)
      0  Win32::API::Struct=HASH(0x1c12730)
         '__typedef__' => 'TCdRom'
         'typedef' => ARRAY(0x1c12550)
            0  ARRAY(0x1c12760)
               0  'HaId'
               1  'i'
               2  'int'
            1  ARRAY(0x1c127a8)
               0  'Target'
               1  'i'
               2  'int'
            2  ARRAY(0x1c127c0)
               0  'Lun'
               1  'i'
               2  'int'
            3  ARRAY(0x1c127fc)
               0  'Vendor'
               1  'c*256'
               2  'char'
            4  ARRAY(0x1c12838)
               0  'ProductId'
               1  'c*256'
               2  'char'
            5  ARRAY(0x1c12874)
               0  'Revision'
               1  'c*256'
               2  'char'
            6  ARRAY(0x1c128b0)
               0  'VendorSpec'
               1  'c*256'
               2  'char'
      1  Win32::API::Struct=HASH(0x1c3e158)
         '__typedef__' => 'TCdRom'
         'typedef' => ARRAY(0x1c12550)
            -> REUSED_ADDRESS
      2  Win32::API::Struct=HASH(0x1c3e194)
         '__typedef__' => 'TCdRom'
         'typedef' => ARRAY(0x1c12550)
            -> REUSED_ADDRESS
      3  Win32::API::Struct=HASH(0x1c3e1d0)
         '__typedef__' => 'TCdRom'
         'typedef' => ARRAY(0x1c12550)
            -> REUSED_ADDRESS
      4  Win32::API::Struct=HASH(0x1c3e20c)
         '__typedef__' => 'TCdRom'
         'typedef' => ARRAY(0x1c12550)
            -> REUSED_ADDRESS

###### Repeat for indexes 5 through 23, and... #######

      24  Win32::API::Struct=HASH(0x1c3e6bc)
         '__typedef__' => 'TCdRom'
         'typedef' => ARRAY(0x1c12550)
            -> REUSED_ADDRESS
      25  Win32::API::Struct=HASH(0x1c3e6f8)
         '__typedef__' => 'TCdRom'
         'typedef' => ARRAY(0x1c12550)
            -> REUSED_ADDRESS
   'Drive[26]' => Win32::API::Struct=HASH(0x1c3e05c)
      '__typedef__' => 'TCdRom'
      'typedef' => ARRAY(0x1c12550)
         -> REUSED_ADDRESS
   '__typedef__' => 'TCdRoms'
   'typedef' => ARRAY(0x1c12778)
      0  ARRAY(0x1c1276c)
         0  'CdRomCount'
         1  'C'
         2  'BYTE'
      1  ARRAY(0x1c12988)
         0  'Drive[26]'
         1  '>'
         2  'TCdRom'

###################
[download]

I don't like that " 'Drive[26]' => Win32::API::Struct=HASH(0x1c3e05c)" after the drive entries, but I don't know how to get rid of it. So, my best guess is I'm passing something wrong as a parameter to GetCdRomDrives, and the function is returning an error. Or maybe it's not returning an error, but it's not returning what I need either (the TCdRoms structure with 1 or 2 entries defined, as I have a CD-ROM and a DVD-ROM drive installed).

Do you have any clues for me? I'm out of guesses.

Thanks a lot,

VMat

In reply to Win32::API arguments by VMat

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