1 files changed, 2 insertions, 1 deletions
diff --git a/walker.h b/walker.h
index 95e5765484..a869013e85 100644
--- a/walker.h
+++ b/walker.h
@@ -19,7 +19,8 @@ struct walker {
 };
 
 /* Report what we got under get_verbosely */
-void walker_say(struct walker *walker, const char *, const char *);
+__attribute__((format (printf, 2, 3)))
+void walker_say(struct walker *walker, const char *fmt, ...);
 
 /* Load pull targets from stdin */
 int walker_targets_stdin(char ***target, const char ***write_ref);