diff --git a/gdk/gdkdebugprivate.h b/gdk/gdkdebugprivate.h
index 63779125ec..e694cb207b 100644
--- a/gdk/gdkdebugprivate.h
+++ b/gdk/gdkdebugprivate.h
@@ -119,3 +119,4 @@ guint gdk_parse_debug_var (const char        *variable,
                            const GdkDebugKey *keys,
                            guint              nkeys);
 
+G_END_DECLS