diff --git a/include/d3d9.h b/include/d3d9.h
index 08f45559134..ef3ea2a9181 100644
--- a/include/d3d9.h
+++ b/include/d3d9.h
@@ -1617,7 +1617,8 @@ DECLARE_INTERFACE_(IDirect3D9Ex, IDirect3D9)
     STDMETHOD_(UINT, GetAdapterModeCountEx)(THIS_ UINT adapter_idx, const D3DDISPLAYMODEFILTER *filter) PURE;
     STDMETHOD(EnumAdapterModesEx)(THIS_ UINT adapter_idx, const D3DDISPLAYMODEFILTER *filter,
             UINT mode_idx, D3DDISPLAYMODEEX *mode) PURE;
-    STDMETHOD(GetAdapterDisplayModeEx)(THIS_ UINT adapter_idx, D3DDISPLAYMODEEX *mode, D3DDISPLAYROTATION *rotation);
+    STDMETHOD(GetAdapterDisplayModeEx)(THIS_ UINT adapter_idx,
+            D3DDISPLAYMODEEX *mode, D3DDISPLAYROTATION *rotation) PURE;
     STDMETHOD(CreateDeviceEx)(THIS_ UINT adapter_idx, D3DDEVTYPE device_type, HWND focus_window, DWORD flags,
             D3DPRESENT_PARAMETERS *parameters, D3DDISPLAYMODEEX *mode, struct IDirect3DDevice9Ex **device) PURE;
     STDMETHOD(GetAdapterLUID)(THIS_ UINT adapter_idx, LUID *luid) PURE;