add: return 0;
context: int add_watcher(presentity_t* _p, str* _from, str* _c, time_t _e, doctype_t _a, str* callid, str* from_tag, str* to, struct watcher** _w){	if (new_watcher(_from, _c, _e, _a, _w, callid, from_tag, to) < 0) {		LOG(L_ERR, "add_watcher(): Error while creating new watcher structure\n");		return -1;	}	(*_w)->next = _p->watchers;	_p->watchers = *_w;}