- std::string Result = irc::stringjoiner(" ", Data.ack, 0, Data.ack.size() - 1).GetJoined();
- user->WriteServ("CAP * ACK :%s", Result.c_str());
+ std::string Result;
+ if (!Data.ack.empty())
+ Result = irc::stringjoiner(" ", Data.ack, 0, Data.ack.size() - 1).GetJoined();
+ user->WriteServ("CAP %s ACK :%s", user->nick.c_str(), Result.c_str());