comctl32/listview: Fix LVM_SETICONSPACING on 64bit machines.

dlls/comctl32/listview.c

@@ -11468,7 +11468,9 @@ LISTVIEW_WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
     return LISTVIEW_SetHoverTime(infoPtr, (DWORD)lParam);
 
   case LVM_SETICONSPACING:
-    return LISTVIEW_SetIconSpacing(infoPtr, (short)LOWORD(lParam), (short)HIWORD(lParam));
+    if(lParam == -1)
+        return LISTVIEW_SetIconSpacing(infoPtr, -1, -1);
+    return LISTVIEW_SetIconSpacing(infoPtr, LOWORD(lParam), HIWORD(lParam));
 
   case LVM_SETIMAGELIST:
     return (LRESULT)LISTVIEW_SetImageList(infoPtr, (INT)wParam, (HIMAGELIST)lParam);

dlls/comctl32/tests/listview.c

@@ -4654,11 +4654,26 @@ static void test_getitemspacing(void)
 
     ret = SendMessage(hwnd, LVM_GETITEMSPACING, FALSE, 0);
     expect(100, LOWORD(ret));
-    expect(0xFFFF, HIWORD(ret));
 
-    ret = SendMessage(hwnd, LVM_SETICONSPACING, 0, -1);
-    expect(100, LOWORD(ret));
     expect(0xFFFF, HIWORD(ret));
+
+    if (sizeof(void*) == 8)
+    {
+        /* NOTE: -1 is not treated the same as (DWORD)-1 by 64bit listview */
+        ret = SendMessage(hwnd, LVM_SETICONSPACING, 0, (DWORD)-1);
+        expect(100, LOWORD(ret));
+        expect(0xFFFF, HIWORD(ret));
+
+        ret = SendMessage(hwnd, LVM_SETICONSPACING, 0, -1);
+        expect(0xFFFF, LOWORD(ret));
+        expect(0xFFFF, HIWORD(ret));
+    }
+    else
+    {
+        ret = SendMessage(hwnd, LVM_SETICONSPACING, 0, -1);
+        expect(100, LOWORD(ret));
+        expect(0xFFFF, HIWORD(ret));
+    }
     ret = SendMessage(hwnd, LVM_GETITEMSPACING, FALSE, 0);
     /* spacing + icon size returned */
     expect(cx + 40, LOWORD(ret));