function KeyHook: Boolean; stdcall;
begin
   SetWindowsHookEx(.....)
   ...
end;    // 讓 KeyHook Export 出去, Ordinal 是由後往前排
exports
  KeyHook;    begin
end.

procedure DllMain(reason: Integer);
begin
  case reason of begin
    DLL_PROCESS_ATTACH:
         OpenFileMapping
         MapViewOfFile         
         ...
    DLL_PROCESS_DETACH:
         ...
         ...    
  end;
end;    begin
  DllProc := @DllMain;
  DllProc(DLL_PROCESS_ATTACH);
end.