Physical vs logical drives in Windows and Lazarus
lazarus / 34-Windows

----------------------------------------------------------------------
pusuni · 2016-05-17 12:56

My system:

C -> SSD
D and E -> HD (the same physical drive)

Is there any manner to detect if the logical drives D and E are in the
same physical drive or not, in Lazarus?

Thanks in advanced

----------------------------------------------------------------------
wp · 2016-05-17 13:40

I found this code on
https://www.eldos.com/forum/read.php?FID=16&TID=6004&MID=33475, it is
Windows-only (tested with Win10), but it hopefully does what you need:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i uses 
Windows,  SysUtils,  ActiveX,  ComObj,  Variants; function ListDrives
: string;var  FSWbemLocator  : Variant;  objWMIService  : Variant; 
colDiskDrives  : Variant;  colLogicalDisks: Variant;  colPartitions  :
Variant;  objdiskDrive   : OLEVariant;  objPartition   : OLEVariant; 
objLogicalDisk : OLEVariant;  oEnumDiskDrive : IEnumvariant; 
oEnumPartition : IEnumvariant;  oEnumLogical   : IEnumvariant;  iValue
        : pULONG;  DeviceID       : widestring;  s : widestring;  n:
LongWord;begin;  Result:='';  FSWbemLocator   :=
CreateOleObject('WbemScripting.SWbemLocator');  objWMIService   :=
FSWbemLocator.ConnectServer('localhost', 'root\CIMV2', '', ''); 
colDiskDrives   := objWMIService.ExecQuery('SELECT DeviceID FROM
Win32_DiskDrive', 'WQL');  oEnumDiskDrive  :=
IUnknown(colDiskDrives._NewEnum) as IEnumVariant;  while
oEnumDiskDrive.Next(1, objdiskDrive, n) = 0 do  begin   
Writeln(Format('DeviceID %s',[string(objdiskDrive.DeviceID)]));   
//Escape the `\` chars in the DeviceID value because the '\' is a
reserved character in WMI.    DeviceID        :=
StringReplace(objdiskDrive.DeviceID,'\','\\',[rfReplaceAll]);   
//link the Win32_DiskDrive class with the
Win32_DiskDriveToDiskPartition class    s:=Format('ASSOCIATORS OF
{Win32_DiskDrive.DeviceID="%s"} WHERE AssocClass =
Win32_DiskDriveToDiskPartition',[DeviceID]);    colPartitions   :=
objWMIService.ExecQuery(s, 'WQL');    oEnumPartition  :=
IUnknown(colPartitions._NewEnum) as IEnumVariant;    while
oEnumPartition.Next(1, objPartition, n) = 0 do    begin      if not
VarIsNull(objPartition.DeviceID) then      begin       
Writeln(Format('   Partition %s',[string(objPartition.DeviceID)]));  
    //link the Win32_DiskPartition class with
theWin32_LogicalDiskToPartition class.        s:='ASSOCIATORS OF
{Win32_DiskPartition.DeviceID="'+VarToStr(objPartition.DeviceID)+'"}
WHERE AssocClass = Win32_LogicalDiskToPartition';       
colLogicalDisks := objWMIService.ExecQuery(s);        oEnumLogical  :=
IUnknown(colLogicalDisks._NewEnum) as IEnumVariant;        while
oEnumLogical.Next(1, objLogicalDisk, n) = 0 do        begin         
Writeln(Format('     Logical Disk
%s',[string(objLogicalDisk.DeviceID)]));         
objLogicalDisk:=Unassigned;        end;      end;     
objPartition:=Unassigned;    end;    objdiskDrive:=Unassigned; 
end;end; begin  try    // CoInitialize(nil); Needed for Delphi but not
Freepascal    try      ListDrives;    finally     // CoUninitialize;
 Needed for Delphi but not Freepascal    end;  except    on
E:EOleException do       Writeln(E.Message + '  Code
'+IntToStr(E.ErrorCode));    on E:Exception do     
 Writeln(E.Classname, ':', E.Message);  end;  Writeln('Done'); 
Readln;end.

----------------------------------------------------------------------
pusuni · 2016-05-18 06:43

Thanks a lot for the info.

----------------------------------------------------------------------
pusuni · 2016-05-18 18:48

Today I've tried to compiler the code in lazarus and it doesn't work
properly. The lines

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i  
objdiskDrive   : OLEVariant;  objPartition   : OLEVariant; 
objLogicalDisk : OLEVariant;
are faulty. Lazarus complains about OLEVariant: it doesn't exist this
data type .

The same code, I compiled  in Free Pascal, is faulty, too.  I had to
change the lines like
QuoteIUnknown(XXX) as IEnumVariant   --> IEnumVariant(XXX)
and I deleted the try / except at the end (I don't understand why
"try" was not recognized by Free Pascal ) , and the code works
properly

Any suggestions?

Best Regards

----------------------------------------------------------------------
molly · 2016-05-18 19:38

@pusuni

which version of lazarus, but more importantly Free Pascal are you
using ?

It compiles fine with FPC 3.0, although i had to add {$MODE OBJFPC}

The only 'warning' i got using OleVariant in a standalone declaration
is that the variants unit is used implicitly: "oleole.pas(10) Warning:
Implicit uses of Variants unit"

Compilling with 2.6.4 got me some errors, but those were more related
to windows and its use of some strange (incompatible) types.

----------------------------------------------------------------------
wp · 2016-05-18 20:40

I had tested with Laz trunk/fpc 3.0. Repeating with Laz 1.6/fpc3.0 is
fine as well. Laz 1.44/fpc2.6.4, however, yields some compiler errors
regarding OLEVariant and LongWord variables - just adapt the variable
declarations to what the compiler requires, and then the program runs
fine also in this tool combination. The same with Laz 1.2.6/fpc 2.6.4.
Did not test older versions, please update in this case.

----------------------------------------------------------------------
pusuni · 2016-05-19 08:44

Quote from: wp on May 18, 2016, 10:40:19 pmI had tested with Laz
trunk/fpc 3.0. Repeating with Laz 1.6/fpc3.0 is fine as well. Laz
1.44/fpc2.6.4, however, yields some compiler errors regarding
OLEVariant and LongWord variables - just adapt the variable
declarations to what the compiler requires, and then the program runs
fine also in this tool combination. The same with Laz 1.2.6/fpc 2.6.4.
Did not test older versions, please update in this case.

I tested with that version: Laz 1.44/fpc2.6.4.

I tested with FPC 3.0, too

QuoteIt compiles fine with FPC 3.0, although i had to add {$MODE
OBJFPC}

I did not know he had to add that code.

Thanks again