diff --git a/gdk/quartz/gdkvisual-quartz.c b/gdk/quartz/gdkvisual-quartz.c
index c597185451..a2de49ae34 100644
--- a/gdk/quartz/gdkvisual-quartz.c
+++ b/gdk/quartz/gdkvisual-quartz.c
@@ -23,9 +23,9 @@
 #include "gdkvisualprivate.h"
 #include "gdkprivate-quartz.h"
 
-GType gdk_quartz_visual_get_type (void);
+GType _gdk_quartz_visual_get_type (void);
 
-#define GDK_TYPE_QUARTZ_VISUAL              (gdk_quartz_visual_get_type ())
+#define GDK_TYPE_QUARTZ_VISUAL              (_gdk_quartz_visual_get_type ())
 #define GDK_QUARTZ_VISUAL(object)           (G_TYPE_CHECK_INSTANCE_CAST ((object), GDK_TYPE_QUARTZ_VISUAL, GdkQuartzVisual))
 #define GDK_QUARTZ_VISUAL_CLASS(klass)      (G_TYPE_CHECK_CLASS_CAST ((klass), GDK_TYPE_QUARTZ_VISUAL, GdkQuartzVisualClass))
 #define GDK_IS_QUARTZ_VISUAL(object)        (G_TYPE_CHECK_INSTANCE_TYPE ((object), GDK_TYPE_QUARTZ_VISUAL))