--- /dev/null
+typedef struct _GtkWidget GtkWidget;
+typedef struct _GtkButton GtkButton;
+
+namespace callbacks {
+
+void OnDestroy(GtkWidget*, gpointer);
+void OnExportClicked(GtkButton*, gpointer);
+void OnAddMaterial(GtkButton*, gpointer);
+void OnRemoveMaterial(GtkButton*, gpointer);
+void OnExportMatClicked(GtkButton* button, gpointer);
+
+}// callbacks