+
+const char* bus_message_get_arg(sd_bus_message *m, unsigned i);
+
+int bus_message_append_ap(sd_bus_message *m, const char *types, va_list ap);
+
+int bus_message_parse_fields(sd_bus_message *m);
+
+int bus_header_size(struct bus_header *h, size_t *sum);
+
+struct bus_body_part *message_append_part(sd_bus_message *m);
+
+#define MESSAGE_FOREACH_PART(part, i, m) \
+ for ((i) = 0, (part) = &(m)->body; (i) < (m)->n_body_parts; (i)++, (part) = (part)->next)