Don't create multiple parent-less top level frames in layout sample.

[wxWidgets.git] / include / wx / gbsizer.h

diff --git a/include/wx/gbsizer.h b/include/wx/gbsizer.h
index 9ee4d4863549f38512bce265a454638b82f1d98f..d9120a607b4a6d24197ae05d154669af35dc678c 100644 (file)
--- a/include/wx/gbsizer.h
+++ b/include/wx/gbsizer.h
@@ -67,6 +67,14 @@ public:
 
     // default copy ctor and assignment operator are okay.
 
+    // Factor constructor creating an invalid wxGBSpan: this is mostly supposed
+    // to be used as return value for functions returning wxGBSpan in case of
+    // errors.
+    static wxGBSpan Invalid()
+    {
+        return wxGBSpan(NULL);
+    }
+
     int GetRowspan() const { return m_rowspan; }
     int GetColspan() const { return m_colspan; }
     void SetRowspan(int rowspan)
@@ -87,6 +95,13 @@ public:
     bool operator!=(const wxGBSpan& o) const { return !(*this == o); }
 
 private:
+    // This private ctor is used by Invalid() only.
+    wxGBSpan(struct InvalidCtorTag*)
+    {
+        m_rowspan =
+        m_colspan = -1;
+    }
+
     void Init()
     {
         m_rowspan =