CODEWITHSUNDEEP
windowsdelphidelphi-2007shortcutmaxlength
Jens Mühlenhoff
Jens Mühlenhoff

Reputation: 14873

Do Windows shortcuts support very long argument lengths?

I am trying to create a shortcut (on the Desktop) that contains a long argument string (> MAX_PATH).

The MSDN documentation clearly states that for Unicode string the string can be longer than MAX_PATH.

The resulting shortcut is cut exactly after MAX_PATH characters (that is the Path + the Arguments).

Is there something wrong with my implementation or is this some Windows limitation?

procedure CreateShortcut(APath: WideString;
  AWorkingDirectory: WideString; AArguments: WideString; ADescription: WideString;
  ALinkFileName: WideString);
var
   IObject : IUnknown;
   ISLink  : IShellLinkW;
   IPFile  : IPersistFile;
begin
   IObject := CreateComObject(CLSID_ShellLink);
   ISLink := IObject as IShellLinkW;
   ISLink.SetPath(            PWideChar(APath));
   ISLink.SetWorkingDirectory(PWideChar(AWorkingDirectory));
   ISLink.SetArguments(       PWideChar(AArguments));
   ISLink.SetDescription(     PWideChar(ADescription));
   IPFile := IObject as IPersistFile;
   IPFile.Save(PWideChar(ALinkFileName), False);
end;

PS: OS is Windows XP (and above).

Upvotes: 8

Views: 15172

Answers (2)

user66001
user66001

Reputation: 935

Thanks all who contributed to this thread - it helped me immensely.

However, if I may, I would like to add the below information I discovered in crafting my solution:

  1. On Windows 7 Enterprise ~SP1, it would seem that using VBS to create the shortcut there is still a limit on maximum characters in (at least) the arguments field. I tested up to 1023 chars before it got trunicated. I presume the same limit would apply to the Delphi method likewise.

  2. On Windows XP Professional ~SP3, while the VBS method will create a shortcut longer than 260 characters (lnk file contains the data), it seems to trunicate it at about this number when executing it.

Upvotes: 7

David Heffernan
David Heffernan

Reputation: 612983

It turns out that this issue is in fact solely a limitation in the Explorer shell dialog. The generated shortcut file does not have a 260 character limitation. It's simply that the dialog refuse to display a Target with more characters than that. Presumably it calls GetPath with a fixed length buffer.

procedure TForm11.Button1Click(Sender: TObject);
var
  sl: IShellLinkW;
  pf: IPersistFile;
begin
  CoCreateInstance(CLSID_ShellLink, nil, 
    CLSCTX_INPROC_SERVER, IID_IShellLinkW, sl);
  sl.SetPath('c:\desktop\test.bat');
  sl.SetWorkingDirectory('c:\desktop\');
  sl.SetArguments(PChar(StringOfChar('x', 300)+'_the_end'));
  pf := sl as IPersistFile;
  pf.Save('c:\desktop\test.lnk', False);
end;

My test.bat looks like this:

echo %1> test.out

The resulting test.out goes right the way to _the_end!

Upvotes: 16

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