void source_description_subscribe();
void source_description_cleanup(struct source_description* desc);
void source_description_add_user_data(Gom_ctxt ctxt, struct user_data* data);
void source_description_subscribe();
void source_description_cleanup(struct source_description* desc);
void source_description_add_user_data(Gom_ctxt ctxt, struct user_data* data);