diff --git a/include/proto/stream.h b/include/proto/stream.h
index e54ac60..69153df 100644
--- a/include/proto/stream.h
+++ b/include/proto/stream.h
@@ -66,7 +66,7 @@
 void stream_dump(struct buffer *buf, const struct stream *s, const char *pfx, char eol);
 void stream_dump_and_crash(enum obj_type *obj, int rate);
 
-int stream_generate_unique_id(struct stream *strm, struct list *format);
+struct ist stream_generate_unique_id(struct stream *strm, struct list *format);
 
 void stream_process_counters(struct stream *s);
 void sess_change_server(struct stream *sess, struct server *newsrv);
diff --git a/include/types/stream.h b/include/types/stream.h
index 90819e6..39a6855 100644
--- a/include/types/stream.h
+++ b/include/types/stream.h
@@ -177,7 +177,7 @@
 	int pcli_next_pid;                      /* next target PID to use for the CLI proxy */
 	int pcli_flags;                         /* flags for CLI proxy */
 
-	char *unique_id;                        /* custom unique ID */
+	struct ist unique_id;                   /* custom unique ID */
 
 	/* These two pointers are used to resume the execution of the rule lists. */
 	struct list *current_rule_list;         /* this is used to store the current executed rule list. */