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