diff --git a/gdk/gdkinternals.h b/gdk/gdkinternals.h
index a187a03106..a14e7abc21 100644
--- a/gdk/gdkinternals.h
+++ b/gdk/gdkinternals.h
@@ -346,8 +346,6 @@ void       _gdk_screen_close             (GdkScreen      *screen);
 void _gdk_cursor_destroy (GdkCursor *cursor);
 
 extern const GOptionEntry _gdk_windowing_args[];
-gchar *_gdk_windowing_substitute_screen_number (const gchar *display_name,
-                                                gint         screen_number);
 
 void _gdk_windowing_got_event                (GdkDisplay       *display,
                                               GList            *event_link,
diff --git a/gdk/quartz/gdkscreen-quartz.c b/gdk/quartz/gdkscreen-quartz.c
index eafaf20c3d..84269f5999 100644
--- a/gdk/quartz/gdkscreen-quartz.c
+++ b/gdk/quartz/gdkscreen-quartz.c
@@ -301,16 +301,6 @@ gdk_quartz_screen_get_number (GdkScreen *screen)
   return 0;
 }
 
-gchar *
-_gdk_windowing_substitute_screen_number (const gchar *display_name,
-					 int          screen_number)
-{
-  if (screen_number != 0)
-    return NULL;
-
-  return g_strdup (display_name);
-}
-
 static gint
 gdk_quartz_screen_get_width (GdkScreen *screen)
 {
diff --git a/gdk/win32/gdkscreen-win32.c b/gdk/win32/gdkscreen-win32.c
index 2e41ea1c10..8cab47117d 100644
--- a/gdk/win32/gdkscreen-win32.c
+++ b/gdk/win32/gdkscreen-win32.c
@@ -147,16 +147,6 @@ gdk_win32_screen_get_number (GdkScreen *screen)
   return 0;
 }
 
-gchar *
-_gdk_windowing_substitute_screen_number (const gchar *display_name,
-					 int          screen_number)
-{
-  if (screen_number != 0)
-    return NULL;
-
-  return g_strdup (display_name);
-}
-
 static gchar *
 gdk_win32_screen_make_display_name (GdkScreen *screen)
 {