msdmo: Fix pointer checking in IEnumDMO_Next().

dlls/msdmo/dmoreg.c

@@ -519,9 +519,12 @@ static HRESULT WINAPI IEnumDMO_fnNext(
 
     TRACE("(%p)->(%d %p %p %p)\n", This, cItemsToFetch, pCLSID, Names, pcItemsFetched);
 
-    if (!pCLSID || !Names || !pcItemsFetched)
+    if (!pCLSID || !Names)
         return E_POINTER;
 
+    if (!pcItemsFetched && cItemsToFetch > 1)
+        return E_INVALIDARG;
+
     while (count < cItemsToFetch)
     {
         This->index++;
@@ -656,8 +659,8 @@ static HRESULT WINAPI IEnumDMO_fnNext(
 	count++;
     }
 
-    *pcItemsFetched = count;
-    if (*pcItemsFetched < cItemsToFetch)
+    if (pcItemsFetched) *pcItemsFetched = count;
+    if (count < cItemsToFetch)
         hres = S_FALSE;
 
     TRACE("<-- %i found\n",count);

dlls/msdmo/tests/msdmo.c

@@ -92,14 +92,21 @@ static void test_DMOEnum(void)
     HRESULT hr;
     CLSID clsid;
     WCHAR *name;
+    DWORD count;
 
     hr = DMOEnum(&GUID_unknowncategory, 0, 0, NULL, 0, NULL, &enum_dmo);
     ok(hr == S_OK, "DMOEnum() failed with %#x\n", hr);
 
     hr = IEnumDMO_Next(enum_dmo, 1, &clsid, &name, NULL);
-    todo_wine
     ok(hr == S_FALSE, "expected S_FALSE, got %#x\n", hr);
 
+    hr = IEnumDMO_Next(enum_dmo, 2, &clsid, &name, NULL);
+    ok(hr == E_INVALIDARG, "expected E_INVALIDARG, got %#x\n", hr);
+
+    hr = IEnumDMO_Next(enum_dmo, 2, &clsid, &name, &count);
+    ok(hr == S_FALSE, "expected S_FALSE, got %#x\n", hr);
+    ok(count == 0, "expected 0, got %d\n", count);
+
     IEnumDMO_Release(enum_dmo);
 }