UPDOWN_GetBuddyInt should not fail when the control is empty.

dlls/comctl32/tests/updown.c

@@ -77,7 +77,7 @@ static void test_updown_control (void)
     hWndUpDown = create_updown_control (hWndEdit);
     /* before we set a value, it should be '0' */
     num = SendMessage(hWndUpDown, UDM_GETPOS, 0, 0L);
-    todo_wine { ok(num == 0, "Expected 0 got %d\n", num); }
+    ok(num == 0, "Expected 0 got %d\n", num);
     /* set a value, check it. */
     SendMessage(hWndUpDown, UDM_SETPOS, 0L, MAKELONG( 1, 0));
     num = SendMessage(hWndUpDown, UDM_GETPOS, 0, 0L);

dlls/comctl32/updown.c

@@ -273,7 +273,10 @@ static BOOL UPDOWN_GetBuddyInt (UPDOWN_INFO *infoPtr)
         if(newVal < 0) return FALSE;
     } else {
         /* we have a regular window, so will get the text */
-        if (!GetWindowTextW(infoPtr->Buddy, txt, COUNT_OF(txt))) return FALSE;
+        /* note that a zero-length string is a legitimate value for 'txt',
+         * and ought to result in a successful conversion to '0'. */
+        if (GetWindowTextW(infoPtr->Buddy, txt, COUNT_OF(txt)) < 0)
+            return FALSE;
 
         sep = UPDOWN_GetThousandSep();