diff --git a/src/Xge.c b/src/Xge.c
index 7a583e5..2ea5d27 100644
--- a/src/Xge.c
+++ b/src/Xge.c
@@ -294,7 +294,7 @@ _xgeEventToWire(Display* dpy, XEvent* re, xEvent* event)
 /*
  * Extensions need to register callbacks for their events.
  */
-Bool
+_X_HIDDEN Bool
 xgeExtRegister(Display* dpy, int offset, XExtensionHooks* callbacks)
 {
     XGEExtNode* newExt;