diff --git a/reactos/dll/directx/ddraw/rosdraw.h b/reactos/dll/directx/ddraw/rosdraw.h
index c1e088ec8ef..82ad296e9e7 100644
--- a/reactos/dll/directx/ddraw/rosdraw.h
+++ b/reactos/dll/directx/ddraw/rosdraw.h
@@ -22,6 +22,7 @@ extern DDRAWI_DIRECTDRAW_GBL ddgbl;
 extern DDRAWI_DDRAWSURFACE_GBL ddSurfGbl;
 extern WCHAR classname[128];
 extern WNDCLASSW wnd_class;
+extern CRITICAL_SECTION ddcs;
 
 
 HRESULT WINAPI StartDirectDraw(LPDIRECTDRAW* iface, LPGUID pGUID, BOOL reenable);