diff --git a/src/ag-chart.c b/src/ag-chart.c
index d1c1be6..1fd96ef 100644
--- a/src/ag-chart.c
+++ b/src/ag-chart.c
@@ -371,3 +371,8 @@ ag_chart_load_from_file(GFile *file, GError **err)
     return chart;
 }
 
+void
+ag_chart_save_to_file(AgChart *chart, GFile *file, GError **err)
+{
+}
+
diff --git a/src/ag-chart.h b/src/ag-chart.h
index 66f3cc3..c8377a7 100644
--- a/src/ag-chart.h
+++ b/src/ag-chart.h
@@ -34,8 +34,7 @@ struct _AgChartClass {
 GType ag_chart_get_type(void) G_GNUC_CONST;
 AgChart *ag_chart_new_full(GsweTimestamp *timestamp, gdouble longitude, gdouble latitude, gdouble altitude, GsweHouseSystem house_system);
 AgChart *ag_chart_load_from_file(GFile *file, GError **err);
-
-void ag_chart_save_to_file(const gchar *path, GError **err);
+void ag_chart_save_to_file(AgChart *chart, GFile *file, GError **err);
 
 void ag_chart_set_name(AgChart *chart, const gchar *name);
 gchar *ag_chart_get_name(AgChart *chart);