1 files changed, 1 insertions, 0 deletions
diff --git a/diff.h b/diff.h
index 870dc91db8..e027650cb0 100644
--- a/diff.h
+++ b/diff.h
@@ -152,6 +152,7 @@ struct diff_options {
 	diff_format_fn_t format_callback;
 	void *format_callback_data;
 	diff_prefix_fn_t output_prefix;
+	int output_prefix_length;
 	void *output_prefix_data;
 };