diff --git a/src/include/66/tree.h b/src/include/66/tree.h
index 64b2f6bd6067f1f2acc385aeb494d6f4b5418d0a..f646c5731ee01f72a99ac71793730689cced6de3 100644
--- a/src/include/66/tree.h
+++ b/src/include/66/tree.h
@@ -40,7 +40,7 @@ extern int tree_get_permissions(char const *tree, uid_t owner) ;
 
 extern int tree_sethome(stralloc *tree, char const *base,uid_t owner) ;
 
-extern char *tree_setname(char const *tree) ;
+extern char tree_setname(stralloc *sa, char const *tree) ;
 
 extern int tree_switch_current(char const *base, char const *tree) ;