c++ - 尝试读取时 QextSerialPort 阻塞

Question

我在 Windows 上使用 QextSerialPort 使我的 Qt/C++ 应用程序能够从串行端口读取和写入串行端口。

我只想在有字节可读的时候才从串口读取字节。

首先，我尝试将 QextSerialPort::readyRead() 信号连接到我的主类中的一个插槽，但我注意到应用程序挂起。

然后我尝试使用 QextSerialPort::read(char *, uint64)，它返回读取的字节数，此后我又尝试结合 QextSerialPort::bytesAvailable() 但未成功 和 QextSerialPort::read(char *, uint64) 看看这是否有助于我的应用程序不被阻塞。

但是，应用程序总是阻塞并且必须被终止，因为它不响应任何鼠标或键盘事件。我认为应用程序卡住是因为读取例程阻塞。

有没有一种方法可以使用 QextSerialPort 执行非阻塞读取？

如果没有，我应该使用什么库来从 Windows 上的串行端口获得非阻塞读取功能？

更新:我尝试使用 QextSerialPort::atEnd() 检查是否有字节要读取，而不是使用 QextSerialPort::bytesAvailable() 或 QextSerialPort::size( ) 并且它始终返回 false。

Answer 1

读取应该是非阻塞的，除非您将查询模式设置为轮询

    inline QueryMode queryMode() const { return _queryMode; }

    /*!
     * Set desired serial communication handling style. You may choose from polling
     * or event driven approach. This function does nothing when port is open; to
     * apply changes port must be reopened.
     *
     * In event driven approach read() and write() functions are acting
     * asynchronously. They return immediately and the operation is performed in
     * the background, so they doesn't freeze the calling thread.
     * To determine when operation is finished, QextSerialPort runs separate thread
     * and monitors serial port events. Whenever the event occurs, adequate signal
     * is emitted.
     *
     * When polling is set, read() and write() are acting synchronously. Signals are
     * not working in this mode and some functions may not be available. The advantage
     * of polling is that it generates less overhead due to lack of signals emissions
     * and it doesn't start separate thread to monitor events.
     *
     * Generally event driven approach is more capable and friendly, although some
     * applications may need as low overhead as possible and then polling comes.