diff --git a/include/fcall.h b/include/fcall.h
index dc46cb5..58323b6 100644
--- a/include/fcall.h
+++ b/include/fcall.h
@@ -44,6 +44,7 @@
 	
 	/* 9P2000.u extensions */
 	int	errornum;	/* Rerror */
+	char	*extension;	/* Tcreate */
 } Fcall;