oleaut32: Fully initialize VARIANT structure in VariantInit().

dlls/oleaut32/tests/vartest.c

@@ -673,11 +673,16 @@ static void _test_bstr_var(unsigned line, const VARIANT *v, const WCHAR *str)
 
 static void test_VariantInit(void)
 {
-  VARIANT v;
+    VARIANT v, v2, v3;
 
-  memset(&v, -1, sizeof(v));
-  VariantInit(&v);
-  ok(V_VT(&v) == VT_EMPTY, "VariantInit() returned vt %d\n", V_VT(&v));
+    memset(&v, -1, sizeof(v));
+    memset(&v2, 0, sizeof(v2));
+    memset(&v3, -1, sizeof(v3));
+    V_VT(&v3) = VT_EMPTY;
+
+    VariantInit(&v);
+    ok(!memcmp(&v, &v2, sizeof(v)) ||
+            broken(!memcmp(&v, &v3, sizeof(v3)) /* pre Win8 */), "Unexpected contents.\n");
 }
 
 /* All possible combinations of extra V_VT() flags */

dlls/oleaut32/variant.c

@@ -545,24 +545,13 @@ static inline HRESULT VARIANT_ValidateType(VARTYPE vt)
 /******************************************************************************
  *		VariantInit	[OLEAUT32.8]
  *
- * Initialise a variant.
- *
- * PARAMS
- *  pVarg [O] Variant to initialise
- *
- * RETURNS
- *  Nothing.
- *
- * NOTES
- *  This function simply sets the type of the variant to VT_EMPTY. It does not
- *  free any existing value, use VariantClear() for that.
+ * Since Windows 8.1 whole structure is initialized, before that only type field was reset to VT_EMPTY.
  */
 void WINAPI VariantInit(VARIANTARG* pVarg)
 {
-  TRACE("(%p)\n", pVarg);
+    TRACE("(%p)\n", pVarg);
 
-  /* Win8.1 zeroes whole struct. Previous implementations don't set any other fields. */
-  V_VT(pVarg) = VT_EMPTY;
+    memset(pVarg, 0, sizeof(*pVarg));
 }
 
 HRESULT VARIANT_ClearInd(VARIANTARG *pVarg)