diff --git a/include/grub/err.h b/include/grub/err.h
index 24ba9f5f5..b08d5d0de 100644
--- a/include/grub/err.h
+++ b/include/grub/err.h
@@ -85,7 +85,8 @@ struct grub_error_saved
 extern grub_err_t EXPORT_VAR(grub_errno);
 extern char EXPORT_VAR(grub_errmsg)[GRUB_MAX_ERRMSG];
 
-grub_err_t EXPORT_FUNC(grub_error) (grub_err_t n, const char *fmt, ...);
+grub_err_t EXPORT_FUNC(grub_error) (grub_err_t n, const char *fmt, ...)
+    __attribute__ ((format (GNU_PRINTF, 2, 3)));
 void EXPORT_FUNC(grub_fatal) (const char *fmt, ...) __attribute__ ((noreturn));
 void EXPORT_FUNC(grub_error_push) (void);
 int EXPORT_FUNC(grub_error_pop) (void);