Mailio

The pop3 class is used for the plain TCP connections, while pop3s must be used for the TLS. It inherits pop3 API but uses TLS. The authentication methods are: login and start tls. For the login method, the well known port is 995:

try
{
    pop3s conn("pop3.server.com", 995);
    conn.authenticate("mailio@server.com", "mailiopass", pop3s::auth_method_t::LOGIN);
    message msg;
    conn.fetch(1, msg);
}
catch (pop3_error& exc)
{
    cout << exc.what() << endl;
}
catch (dialog_error& exc)
{
    cout << exc.what() << endl;
}

try
{
    pop3s conn("pop3.server.com", 110);
    conn.authenticate("mailio@server.com", "mailiopass", pop3s::auth_method_t::START_TLS);
    message msg;
    conn.fetch(1, msg);
}
catch (pop3_error& exc)
{
    cout << exc.what() << endl;
}
catch (dialog_error& exc)
{
    cout << exc.what() << endl;
}