Delphi - on-screen keyboard (osk.exe) works on Win32, but does not work on Win64

Question

I am trying to launch an on-screen keyboard from my application. It works correctly in Windows XP 32 bits, but incorrectly in Win 7 64 bits.

unit Unit5;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ShellAPI;

type
  TForm5 = class(TForm)
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
   class function IsWOW64: Boolean;
    { Public declarations }
  end;

var
  Form5: TForm5;

implementation

{$R *.dfm}


procedure TForm5.FormCreate(Sender: TObject);
var path:String;
    res : Integer;

function GetSysDir: string;
var
  Buf: array[0..MAX_PATH] of Char;
  Len: UINT;
  S: String;
begin
  {$IFNDEF WIN64}
  if TForm5.IsWOW64 then
  begin
    Len := GetWindowsDirectory(Buf, MAX_PATH);
    if Len = 0 then RaiseLastOSError;
    SetString(S, Buf, Len);
    Result := IncludeTrailingPathDelimiter(S) + 'Sysnative\';
    Exit;
  end;
  {$ENDIF}
  Len := GetSystemDirectory(Buf, MAX_PATH);
  if Len = 0 then RaiseLastOSError;
  SetString(S, Buf, Len);
  Result := IncludeTrailingPathDelimiter(S);
end;

begin
 path := GetSysDir;

 path := path + 'osk.exe';

  res := ShellExecute(self.Handle,'open',Pchar(path),nil,nil,SW_NORMAL);

 if res <> 42 then
  begin
   ShowMessage(path);
   RaiseLastOSError;
  end;
end;

class function TForm5.IsWOW64: Boolean;
type
  TIsWow64Process = function( // Type of IsWow64Process API fn
    Handle: THandle;
    var Res: BOOL
  ): BOOL; stdcall;
var
  IsWow64Result: BOOL;              // result from IsWow64Process
  IsWow64Process: TIsWow64Process;  // IsWow64Process fn reference
begin
  // Try to load required function from kernel32
  IsWow64Process := GetProcAddress(
    GetModuleHandle('kernel32'), 'IsWow64Process'
  );
  if Assigned(IsWow64Process) then
  begin
    // Function is implemented: call it
    if not IsWow64Process(GetCurrentProcess, IsWow64Result) then
     RaiseLastOSError;
    // Return result of function
    Result := IsWow64Result;
  end
  else
    // Function not implemented: can't be running on Wow64
    Result := False;
end;


end.

Running the application on x64 shows the path C: \ Windows \ Sysnative \ osk.exe and causes the error "function call failed operating system".

A search in the Windows directories shows that osk.exe exists

Answer 1

UAC has something special about osk. This code fails with the error code 740 ERROR_ELEVATION_REQUIRED. The requested operation requires a promotion.

var
  si: TStartupInfo;
  pi: TProcessInformation;
....
si.cb := SizeOf(si);
GetStartupInfo(si);
Win32Check(CreateProcess('C:\Windows\system32\osk.exe', nil, nil, nil, 
  False, 0, nil, nil, si, pi));

32, 64- UAC. : http://blog.delphi-jedi.net/2008/05/17/the-case-of-shellexecute-shellexecuteex-createprocess-and-oskexe/

, 32 64 , , XP UAC.

, , , ShellExecute. 16- . , ShellExecuteEx. , , CreateProcess API .

, osk , CreateProcess. ShellExecute ShellExecuteEx. UAC. , 32- WOW64-. osk 64- ShellExecuteEx.

:

• 32- ShellExecuteEx, osk.
• 64- , 64 , ShellExecuteEx, osk.
• 64- , 32- WOW64-, 64- , ShellExecuteEx, osk.

, , 64- Delphi, 64- . 64- fpc 64- ++-. ++ :

#include <Windows.h>
#include <Shellapi.h>

int CALLBACK WinMain(
  HINSTANCE hInstance,
  HINSTANCE hPrevInstance,
  LPSTR lpCmdLine,
  int nCmdShow
)
{
    SHELLEXECUTEINFOW sei = { sizeof(sei) };
    sei.lpVerb = L"open";
    sei.lpFile = L"osk.exe";
    sei.nShow = SW_SHOW;
    ShellExecuteExW(&sei);
}

64- ++, 32- WOW64-. , !