diff --git a/fuse/guestmount.c b/fuse/guestmount.c
index 17e94ba87..1eb0553b6 100644
--- a/fuse/guestmount.c
+++ b/fuse/guestmount.c
@@ -49,7 +49,7 @@ static int write_pid_file (const char *pid_file, pid_t pid);
  * Copyright (C) 2001-2007  Miklos Szeredi <miklos@szeredi.hu>
  * This [function] can be distributed under the terms of the GNU LGPLv2.
  */
-static int
+static void
 fuse_opt_add_opt_escaped (char **opts, const char *opt)
 {
   unsigned oldlen = *opts ? strlen(*opts) : 0;