QT5 信号槽重载

//方法1
void (QTcpSocket::*onErr)(QAbstractSocket::SocketError) = &QTcpSocket::error;
connect(m_tcpClient, onErr, this, &TcpClient::onTcpError);
	
//方法2
connect(m_tcpClient, static_cast<void (QTcpSocket::*)(QAbstractSocket::SocketError)>(&QTcpSocket::error), this, &TcpClient::onTcpError);

//方法3
typedef void (QTcpSocket::*TcpSignal)(QAbstractSocket::SocketError);
connect(m_tcpClient, static_cast<TcpSignal>(&QTcpSocket::error), this, &TcpClient::onTcpError);