diff --git a/include/9p.h b/include/9p.h
index 00d2fe0..f83dce0 100644
--- a/include/9p.h
+++ b/include/9p.h
@@ -219,7 +219,7 @@
 void		srv(Srv*);
 void		postmountsrv(Srv*, char*, char*, int);
 int 		postfd(char*, int);
-int		chatty9p;
+extern	int		chatty9p;
 void		respond(Req*, char*);
 void		threadpostmountsrv(Srv*, char*, char*, int);