Delphi DDE Server Connecting Non-Delphi DDE Client (MS Excel, Word and etc) Problem!

I've converted a Microsoft DDE server sample application from C++ to Delphi.
My Delphi DDE server works well in Windows9x connecting to Excel 97. But it
does not work with Windows XP connecting to Excel 97. Then I programmed a
DDE client in Delphi and surprisingly, it works well with my Delphi DDE
Server. But when i tried to connect the Delphi DDE client to the C++ DDE
server, it doesn't work.

I guess Excel was written in C/C++ and that's why it doesn't work with my
Delphi DDE server. I also noticed that Excel can get the data in it's first
request with XTYP_REQUEST and then it can't get subsequent data updates with
XTYP_ADVREQ. Something wrong somewhere in XTYP_ADVREQ or DdePostAdvise?

I've included the related source code below. Please take a look...

//---------------------------------- MS DDE Server Example
#include <windows.h>
#include <stdio.h>
#include <ddeml.h>


// Globals...
HSZ g_hszAppName;
HSZ g_hszTopicName;
HSZ g_hszItemName;
int g_count = 0;
DWORD g_idInst = 0;

// Declarations:
HDDEDATA EXPENTRY DdeCallback(UINT type, UINT fmt, HCONV hConv, HSZ hsz1,
HSZ hsz2, HDDEDATA hData, DWORD dwData1, DWORD dwData2);

// WinMain()..
int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR
lpCmdLine, int nCmdShow) {

   // Initialize DDEML...
   if(DdeInitialize(&g_idInst, DdeCallback, APPCLASS_STANDARD, 0)) {
      MessageBox(NULL, "DdeInitialize() failed", "Error", MB_SETFOREGROUND);
      return -1;
   }

   // Create string handles...
   g_hszAppName = DdeCreateStringHandle(g_idInst, "DdemlSvr", NULL);
   g_hszTopicName = DdeCreateStringHandle(g_idInst, "MyTopic", NULL);
   g_hszItemName = DdeCreateStringHandle(g_idInst, "MyItem", NULL);

   if( (g_hszAppName == 0) || (g_hszTopicName == 0) || (g_hszItemName ==
0) ) {
      MessageBox(NULL, "DdeCreateStringHandle() failed", "Error",
MB_SETFOREGROUND);
      return -2;
   }

   // Register DDE server
   if(!DdeNameService(g_idInst, g_hszAppName, NULL, DNS_REGISTER)) {
      MessageBox(NULL, "DdeNameService() failed!", "Error",
MB_SETFOREGROUND);
      return -3;
   }

   // Create a timer to simulate changing data...
   SetTimer(0,0,1,0);

   // Message loop:
   MSG msg;

   while (GetMessage(&msg, NULL, 0, 0))  {
      // On WM_TIMER, change our counter, and update clients...
      if(msg.message == WM_TIMER) {
         g_count++;
         DdePostAdvise(g_idInst, g_hszTopicName, g_hszItemName);
      }
      TranslateMessage(&msg);
      DispatchMessage(&msg);
   }

   return msg.wParam;
}


// Our DDE Callback function...
HDDEDATA EXPENTRY DdeCallback(UINT wType, UINT fmt, HCONV hConv, HSZ hsz1,
HSZ hsz2, HDDEDATA hData, DWORD dwData1, DWORD dwData2) {

   switch (wType) {

   // ----------------------------------------------------------------
   case XTYP_CONNECT:
      // Client is trying to connect. Respond TRUE if we have what they
want...
      if ((!DdeCmpStringHandles(hsz1, g_hszTopicName)) &&
         (!DdeCmpStringHandles(hsz2, g_hszAppName)))
         return (HDDEDATA)TRUE;   // SERVER supports Topic|Service
      else
         return FALSE;  // SERVER does not support Topic|Service

      // ----------------------------------------------------------------
   case XTYP_ADVSTART:
      // Client starting advisory loop.
      // Say "ok" if we have what they are asking for...

      if((!DdeCmpStringHandles(hsz1, g_hszTopicName)) &&
         (!DdeCmpStringHandles(hsz2, g_hszItemName)))
         return (HDDEDATA)TRUE;   // SERVER supports Topic|Service
      else
         return FALSE;  // SERVER does not support Topic|Service
      // ----------------------------------------------------------------


   case XTYP_ADVREQ:

      // Client wants our data. Since this is specific to Excel, we'll
      // go ahead and assume they want XlTable-formatted data. For a
      // generic DDE server, you might want to handle various formats
      // specified by the passed in fmt parameter.

      if(!DdeCmpStringHandles(hsz1, g_hszTopicName) &&
         !DdeCmpStringHandles(hsz2, g_hszItemName)) {

         short xltableData[100];

         // tdtTable record...
         xltableData[0] = 0x0010; // tdtTable
         xltableData[1] = 4; // 2 short ints following
         xltableData[2] = 1; // # rows
         xltableData[3] = 1; // # cols

         // tdtInt record...
         xltableData[4] = 0x0006;
         xltableData[5] = 2;
         xltableData[6] = (short)g_count;

         return DdeCreateDataHandle(g_idInst, (UCHAR*)xltableData, 2*7, 0,
g_hszItemName, fmt, 0);
      }
      // ----------------------------------------------------------------
   default:
      return (HDDEDATA)NULL;
   }
}

//---------------------------------- MS DDE Server Example


//---------------------------------- Delphi DDE Server
unit uMain;

{$R-,T-,H+,X+}

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  WinTypes, DDEML, ExtCtrls, StdCtrls;

type
  TMainForm = class(TForm)
    lbCount: TLabel;
    Timer1: TTimer;
    lbCallType: TLabel;
    lbResult: TLabel;
    procedure FormCreate(Sender: TObject);
    procedure Timer1Timer(Sender: TObject);
  private
    { Private declarations }
    g_hszAppName: hsz;
    g_hszTopicName: hsz;
    g_hszItemName: hsz;
    g_count: Integer;
    g_idInst: LongInt;
    SentData: array [0..254] of Char;

    function GetDdeError():String;
  public
    { Public declarations }
  end;

var
  MainForm: TMainForm;

function DDECallback(CallType, Fmt: UINT; Conv: HConv; hsz1, hsz2: HSZ;
    Data: HDDEData; Data1, Data2: DWORD): HDDEData; stdcall; export;

implementation

{$R *.DFM}

procedure TMainForm.FormCreate(Sender: TObject);
var
  Result: Word;
  TempStr: String;

begin
  g_count := 0;
  g_idInst := 0;
  g_hszAppName := 0;
  g_hszTopicName := 0;
  g_hszItemName := 0;
  Result := DdeInitialize(g_idInst, DdeCallback, APPCLASS_STANDARD, 0);
  if Result <> DMLERR_NO_ERROR then
  begin
    TempStr := 'Error: DdeInitialize - ' + GetDdeError;
    ShowMessage(TempStr);
    Exit;
  end;

  // Create string handles...
  g_hszAppName := DdeCreateStringHandle(g_idInst, 'DDEServer', CP_WINANSI);
  g_hszTopicName := DdeCreateStringHandle(g_idInst, 'MyTopic', CP_WINANSI);
  g_hszItemName := DdeCreateStringHandle(g_idInst, 'MyItem', CP_WINANSI);
  if (g_hszAppName = 0) or (g_hszTopicName = 0) or (g_hszItemName = 0) then
  begin
    TempStr := 'Error: DdeCreateStringHandle - ' + GetDdeError;
    ShowMessage(TempStr);
    Exit;
  end;

  // Register DDE server
  if DdeNameService(g_idInst, g_hszAppName, 0, DNS_REGISTER) = 0 then
  begin
    TempStr := 'Error: DdeCreateStringHandle - ' + GetDdeError;
    ShowMessage(TempStr);
    Exit;
  end;

end;

function TMainForm.GetDdeError():String;
var
  DDEError: Word;
begin
  DDEError := DdeGetLastError(g_idInst);
  case DDEError of
    DMLERR_ADVACKTIMEOUT: Result := 'Timeout on sync advise request';
    DMLERR_BUSY: Result := 'Server is busy';
    DMLERR_DATAACKTIMEOUT: Result := 'Timeout on sync data request';
    DMLERR_DLL_NOT_INITIALIZED: Result := 'DDEML not initialised';
    DMLERR_DLL_USAGE: Result := 'Invalid request';
    DMLERR_EXECACKTIMEOUT: Result := 'Timeout on sync exec request';
    DMLERR_INVALIDPARAMETER: Result := 'Invalid parameter in request';
    DMLERR_LOW_MEMORY: Result := 'Server ran out of buffer memory';
    DMLERR_MEMORY_ERROR: Result := 'Memory allocation error';
    DMLERR_NO_CONV_ESTABLISHED: Result := 'No conversation established';
    DMLERR_NOTPROCESSED: Result := 'Request not processed by server';
    DMLERR_POKEACKTIMEOUT: Result := 'Timeout on sync poke request';
    DMLERR_POSTMSG_FAILED: Result := 'PostMessage failed';
    DMLERR_REENTRANCY: Result := 'Sync request already in progress';
    DMLERR_SERVER_DIED: Result := 'Server died';
    DMLERR_SYS_ERROR: Result := 'DDEML Internal error';
    DMLERR_UNADVACKTIMEOUT: Result := 'Timeout on unadvise request';
    DMLERR_UNFOUND_QUEUE_ID: Result := 'Invalid transaction ID';
  end;
end;

function DDECallback(CallType, Fmt: UINT; Conv: HConv; hsz1, hsz2: HSZ;
    Data: HDDEData; Data1, Data2: DWORD): HDDEData; stdcall;
var
  DataSize: Word;
  xltableData: array [0..99] of Shortint;

begin
  case CallType of
    XTYP_CONNECT:
    begin
      MainForm.lbCallType.Caption := 'XTYP_CONNECT';
      if (DdeCmpStringHandles(hsz1, MainForm.g_hszTopicName) = 0) and
         (DdeCmpStringHandles(hsz2, MainForm.g_hszAppName)= 0) then
         Result := HDDEDATA(TRUE)   // SERVER supports Topic|Service
      else
         Result := 0;  // SERVER does not support Topic|Service
    end;
    XTYP_ADVSTART:
    begin
      MainForm.lbCallType.Caption := 'XTYP_ADVSTART';
      if (DdeCmpStringHandles(hsz1, MainForm.g_hszTopicName) = 0) and
         (DdeCmpStringHandles(hsz2, MainForm.g_hszItemName)= 0) then
         Result := HDDEDATA(TRUE)
      else
         Result := 0;
    end;
    XTYP_ADVREQ, XTYP_REQUEST:
    begin
      MainForm.lbCallType.Caption := 'XTYP_ADVREQ';
      if (DdeCmpStringHandles(hsz1, MainForm.g_hszTopicName) = 0) and
         (DdeCmpStringHandles(hsz2, MainForm.g_hszItemName)= 0) then
      begin

        {// tdtTable record...
        xltableData[0] := $0010; // tdtTable
        xltableData[1] := $0004; // 2 short ints following
        xltableData[2] := $0001; // # rows
        xltableData[3] := $0001; // # cols

        // tdtInt record...
        xltableData[4] := $0006;
        xltableData[5] := $0002;
        xltableData[6] := Shortint(MainForm.g_count);

        DataSize := SizeOf(xltableData);
        Result := DdeCreateDataHandle(MainForm.g_idInst, @xltableData,
DataSize, 0,
        MainForm.g_hszItemName, fmt, 0);}
        StrCopy(MainForm.SentData, PChar(IntToStr(MainForm.g_count)));
        Result := DdeCreateDataHandle(MainForm.g_idInst, @MainForm.SentData,
StrLen(MainForm.SentData) + 1
        , 0, MainForm.g_hszItemName, CF_TEXT, 0);
      end;
    end
    else
      Result := HDDEDATA(nil);
  end;
  MainForm.lbResult.Caption := IntToStr(Result);
end;

procedure TMainForm.Timer1Timer(Sender: TObject);
begin
  Inc(g_count);
  lbCount.Caption := IntToStr(g_count);
  DdePostAdvise(g_idInst, g_hszTopicName, g_hszItemName);
end;

end.

//---------------------------------- Delphi DDE Server