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I have a Windows Service that creates a WindowClass inside it. This window will be used to make IPC (inter-process communication) between 2 programs.

This service works 100% correctly in:

  • Windows XP
  • Windows Vista (32 and 64 bits)
  • Windows 7 (32 and 64 bits)
  • Windows 8 (32 and 64 bits)
  • Windows Server 2003
  • Windows Server 2008 R2 (32 and 64 bits)

Only on Windows Server 2008 Standart it doesn't works, resulting the error:

 System Error. Code: 8. Not enough storage is available to process this command.

This is the code:

constructor TMyIPC.Create;

  function _CreateUUID: string;
  var
    g: TGUID;
  begin
    if CreateGUID(g) = S_OK then
      Result := GUIDToString(g)
    else
      Result := FormatDateTime('yyyyMMddhhnnsszzz', now);
  end;

begin
  FillChar(fWndClass, sizeOf(fWndClass), 0);
  with fWndClass do
  begin
    lpfnWndProc := @DefWindowProc;
    lpszClassName := StrNew(PChar(_CreateUUID));
  end;

  fObjectInst := classes.MakeObjectInstance(WndProc);

  if RegisterClass(fWndClass) = 0 then
    RaiseLastOSError;

  fHandle := CreateWindow(fWndClass.lpszClassName, fWndClass.lpszClassName,
    WS_POPUP or WS_CAPTION or WS_CLIPSIBLINGS or WS_SYSMENU
    or WS_MINIMIZEBOX,
    GetSystemMetrics(SM_CXSCREEN) div 2,
    GetSystemMetrics(SM_CYSCREEN) div 2,
    0, 0, 0, 0, HInstance, nil);

  if fHandle = 0 then
    RaiseLastOSError;  

  SetWindowLong(fHandle, GWL_WNDPROC, Longint(fObjectInst));
end;

I already verified this question System Error. Code: 8. Not enough storage is available to process this command but it isn't the case (I run the same code inside a VCL application and the error doesn't occurs, it only occurs running inside a service).

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Beto Neto
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    Surely you'd want `HWND_MESSAGE` for a message only window? But in any case, you won't be able to do IPC this way. I presume you want IPC between a desktop app and a service. Well, desktop apps cannot send messages to windows in different sessions. – David Heffernan Aug 05 '13 at 17:17
  • Agreed. Window messages are not a good IPC mechanism for use in services. There are many other IPC mechanisms available that are more service-friendly - named pipes, mailslots, ActiveX/COM, RPC, sockets, etc. – Remy Lebeau Aug 05 '13 at 17:22
  • No, the IPC will be in the same session. It's a "plugin engine" for my application, to isolate the main application memory and the plugins memory. As I mentioned above "it already works, but only at 2008 server standard it dosen't works!" – Beto Neto Aug 05 '13 at 18:26
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    I solved with 2 fixes: disabling UAC and increased HEAP for non-interactive sessions (as mentioned here http://stackoverflow.com/a/508847/1470436). I haven't the correct fix because I haven't a test environment it. This was a end-user environment and I wasn't able to stop and test one at a time... – Beto Neto Aug 05 '13 at 18:35

0 Answers0