Socket and Threads, Halting when Joining, C++

Question

I have a server and a client talking. My server handles each client with a thread. The server code looks like this:

Server::Server(int port)throw (const char*) {
    fd = socket(AF_INET, SOCK_STREAM, 0);
    if (fd<0) {
        throw "socket failed";
    }
    server.sin_family = AF_INET;
    server.sin_addr.s_addr = INADDR_ANY;
    server.sin_port = htons(port);

    if ((::bind(fd, (struct sockaddr*) &server, sizeof(server))) < 0) {
        throw "bind failed";
    }

    if(listen(fd,3)<0) {
        throw "linsten failed";
    }
}

void Server::start(ClientHandler& ch)throw(const char*){
    t = new thread([&ch,this]() {
        while (!stopAccept) {
            cout<<"waiting for a client\n";
            socklen_t clientSize = sizeof(client);
            int aClient = ::accept(fd,(struct sockaddr *)&client, &clientSize);
            if (aClient<0) {
                throw "except failure";
            }
            cout<<"client connected\n";
            ch.handle(aClient);
            close(aClient);
            cout<<"client closed\n";
        }
        close(fd);
    });
}

void Server::stop(){
    stopAccept = true;
    t->join(); // do not delete this!
}

What happens is that after it finished dealing with 2 clients, I call the stop function. But it right away prints "waiting for a client\n", before stopping.

Then, it of course will never stop, because it won't get any other message.

How can I end this program after the second client? A tip from my professor was to "implement a timeout on accept (for ex with alarm)". I have looked online a lot but can't seem to find a way to do this.

Advice?