diff --git a/gdk/x11/gdkx11utils.h b/gdk/x11/gdkx11utils.h
index 9fdeac68a9..573e2ecce1 100644
--- a/gdk/x11/gdkx11utils.h
+++ b/gdk/x11/gdkx11utils.h
@@ -54,15 +54,17 @@ Display *gdk_x11_get_default_xdisplay     (void);
 
 /**
  * GDK_XID_TO_POINTER:
+ * @xid: XID to stuff into the pointer
  *
  * Converts an XID into a @gpointer. This is useful with data structures
  * that use pointer arguments such as #GHashTable. Use GDK_POINTER_TO_XID()
  * to convert the argument back to an XID.
  */
-#define GDK_XID_TO_POINTER(pointer) GUINT_TO_POINTER(pointer)
+#define GDK_XID_TO_POINTER(xid) GUINT_TO_POINTER(xid)
 
 /**
  * GDK_POINTER_TO_XID:
+ * @pointer: pointer to extract an XID from
  *
  * Converts a @gpointer back to an XID that was previously converted
  * using GDK_XID_TO_POINTER().