Close() trigger runtime_error exception when device has been plugged out

[xuniuer]

Hi Sir,

I use a usb type serial device, which is shown as /dev/ttyUSB0 when plugged in. In general, everything is OK by using libserial. Of course when device is plugged out, the related serial operation will throw exceptions.

However, when I re-plug the device in, the port changed to '/dev/ttyUSB1'. I think if I close the previous opened port in time, the port name will still be '/dev/ttyUSB0', if the time interval of plug action is enough long.

Then I try to close opened port, runtime_error exception thrown. Seems that the SerialPort cannot be released normally in this case. The following is Close() code:

    inline
    void
    SerialPort::Implementation::Close()
    {
        // Throw an exception if the serial port is not open.
        if (not this->IsOpen())
        {
            throw NotOpen(ERR_MSG_PORT_NOT_OPEN) ;
        }

        // Restore the old settings of the port.
        if (tcsetattr(this->mFileDescriptor,
                      TCSANOW,
                      &mOldPortSettings) < 0)
        {
            throw std::runtime_error(std::strerror(errno)) ;
        }

        // Otherwise, close the serial port and set the file descriptor
        // to an invalid value.
        if (close(this->mFileDescriptor) < 0) 
        {
            throw std::runtime_error(std::strerror(errno)) ;
        } 

        // Set the file descriptor to an invalid value, -1. 
        mFileDescriptor = -1 ;
    }

Based above, the Close() cannot be finished when a opened port has been removed. Is it an issue?

[xuniuer]

I try to comment out some lines to 'solve' the program:

inline
    void
    SerialPort::Implementation::Close()
    {
        // Throw an exception if the serial port is not open.
        if (not this->IsOpen())
        {
            throw NotOpen(ERR_MSG_PORT_NOT_OPEN) ;
        }
        
        // Modification here - comment out the code block
        // Restore the old settings of the port.
        //if (tcsetattr(this->mFileDescriptor,
        //              TCSANOW,
        //              &mOldPortSettings) < 0)
        //{
        //    throw std::runtime_error(std::strerror(errno)) ;
        // }

        // Otherwise, close the serial port and set the file descriptor
        // to an invalid value.
        if (close(this->mFileDescriptor) < 0) 
        {
            throw std::runtime_error(std::strerror(errno)) ;
        } 

        // Set the file descriptor to an invalid value, -1. 
        mFileDescriptor = -1 ;
    }