비슷한 예입니다.  타이머 쓰실때~

class TfmMain : TFrom
{
public:
    static void CALLBACK TimerProc(UINT uID, UINT uMsg, DWORD dwUser, DWORD dw1, DWORD dw2);
    void __fastcall OnTimer(UINT nIDEvent);
};
//---------------------------------------------------------------------------
void __fastcall TfmMain::FormCreate(TObject *Sender)
{
    // multimedia timer start
    FTimeSetEventID = timeSetEvent(1000, 1, TimerProc, (DWORD)this, TIME_PERIODIC|TIME_CALLBACK_FUNCTION);
}
//---------------------------------------------------------------------------
void CALLBACK TfmMain::TimerProc(UINT uID, UINT uMsg, DWORD dwUser, DWORD dw1, DWORD dw2)
{
   TfmMain* fmMain = (TfmMain*)dwUser;
   try
   {
       if (::IsWindow(fmMain->Handle))
       {
            fmMain->OnTimer(uID);
       }
   }
   catch(...)
   {
   }
}
//---------------------------------------------------------------------------
void __fastcall TfmMain::OnTimer(UINT nIDEvent)
{
    this->Caption = Now().DateTimeString();
}
//---------------------------------------------------------------------------