Qt TCP/IP 套接字连接检查 [英] Qt TCP/IP socket connection check

问题描述

我正在编写 Qt TCP/IP 客户端.我想在将数据发送到服务器之前检查与服务器的连接状态.据我所知，我可以通过以下方法做到这一点

I am writing Qt TCP/IP client. I want to check the connection state with server before send data to sever. As far my knowledge I can do this by following methods

• 使用 bool 'ConnectionState'，连接时设置此变量在 disconnected() 信号时切断并重置此变量.现在之前向服务器发送数据(client->write())检查 this 的值多变的.
• 使用这种client->state() == QTcpSocket::ConnectedState"方式来检查连接状态.

• Use a bool 'ConnectionState', set this variable when connected with sever and reset this variable on disconnected() signal. Now before sending data to server (client->write()) check the value of this variable.
• use this 'client->state() == QTcpSocket::ConnectedState' way to check the connection state.

这是一个很好的做法.或任何其他方法.

Which is good practice. Or any other method to this.

提前致谢.

推荐答案

QTCPSocket 派生自 QAbstractSocket，它提供了一个 state()功能.这将返回以下枚举之一:-

QTCPSocket is derived from QAbstractSocket, which provides a state() function. This returns one of the following enums: -

enum SocketState { UnconnectedState, HostLookupState, ConnectingState, ConnectedState, ..., ListeningState }

因此，假设 m_pSocket 是一个 QTcpSocket，您只需执行此操作来检查它是否已连接:-

So, assuming m_pSocket is a QTcpSocket, you would simply do this to check if it is connected:-

bool connected = (m_pSocket->state() == QTcpSocket::ConnectedState);

您可以添加一个布尔值并跟踪状态，但如果发生网络错误，您需要确保它始终与实际连接状态同步.

You could add a boolean and keep track of the state, but if a network error occurs you need to ensure that it is always in-sync with the actual connection state.

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