fd_set readset, writeset;
FD_ZERO(&readset);
FD_SET(JohnDoe.read_fd(), &readset);
FD_SET(JoeSmith.read_fd(), &readset);
FD_SET(JaneSmith.read_fd(), &readset);
FD_ZERO(&writeset);
FD_SET(JohnDoe.write_fd(), &writeset);
FD_SET(JoeSmith.write_fd(), &writeset);
FD_SET(JaneSmith.write_fd(), &writeset);

int maxfd = 0;
maxfd = max(maxfd, JohnDoe.read_fd());
maxfd = max(maxfd, JohnDoe.write_fd());
maxfd = max(maxfd, JoeSmith.read_fd());
maxfd = max(maxfd, JoeSmith.write_fd());
maxfd = max(maxfd, JaneSmith.read_fd());
maxfd = max(maxfd, JaneSmith.write_fd());

int numready;
int count = 0;
while (count < 10) {
    numready = select(maxfd + 1, &readset, &writeset, NULL, NULL);
    if (numready == -1) {
        cout << "Fatal error, abortingn";
        break;
    }
    else {
        if(FD_ISSET(JohnDoe.write_fd(), &writeset)) { //write_fd() returns write file descriptor
            JohnDoe.cwrite("data John Doe"); //one RequestChannel object
        }
        if(FD_ISSET(JoeSmith.write_fd(), &writeset)) {
            JoeSmith.cwrite("data Joe Smith");
        }
        if(FD_ISSET(JaneSmith.write_fd(), &writeset)) {
            JaneSmith.cwrite("data JaneSmith");
        }



        if(FD_ISSET(JohnDoe.read_fd(), &readset)) {
            string s = JohnDoe.cread();
            cout << "John Doe cread: " << s << "n";
        }
        if(FD_ISSET(JoeSmith.read_fd(), &readset)) {
            string s = JoeSmith.cread();
            cout << "Joe Smith cread: " << s << "n";
        }
        if(FD_ISSET(JaneSmith.read_fd(), &readset)) {
            string s = JaneSmith.cread();
            cout << "Jane Smith cread: " << s << "n";
        }
    }
}

fd_set readset, writeset;

int maxfd = 0;
maxfd = max(maxfd, JohnDoe.read_fd());
maxfd = max(maxfd, JohnDoe.write_fd());
maxfd = max(maxfd, JoeSmith.read_fd());
maxfd = max(maxfd, JoeSmith.write_fd());
maxfd = max(maxfd, JaneSmith.read_fd());
maxfd = max(maxfd, JaneSmith.write_fd());

int numready;
int count = 0;
while (count < 10) {
    FD_ZERO(&readset);
    FD_SET(JohnDoe.read_fd(), &readset);
    FD_SET(JoeSmith.read_fd(), &readset);
    FD_SET(JaneSmith.read_fd(), &readset);
    FD_ZERO(&writeset);
    FD_SET(JohnDoe.write_fd(), &writeset);
    FD_SET(JoeSmith.write_fd(), &writeset);
    FD_SET(JaneSmith.write_fd(), &writeset);

    numready = select(maxfd + 1, &readset, &writeset, NULL, NULL);

    // etc...

}