diff --git a/lib/dircallback.h b/lib/dircallback.h
index 32341133..50eaf7a7 100644
--- a/lib/dircallback.h
+++ b/lib/dircallback.h
@@ -22,6 +22,7 @@
 struct saved_cwd;
 
 int run_in_dirfd (int fd, int (*callback)(void*), void *usercontext);
-int run_in_dir (struct saved_cwd*, int (*callback)(void*), void *usercontext);
+int run_in_dir (const struct saved_cwd*, int (*callback)(void*),
+		void *usercontext);
 
 #endif