Golang Termios.Cc方法代碼示例

// Open a connection with a read timeout.
func (connection *Connection) Open(timeout uint8) error {

	var err error

	// The serial port is basically a file we are writing to and reading from.
	// 	O_RDWR allows the program to read and write the file.
	// 	O_NOCTTY prevents the device from controlling the terminal.
	// 	O_NONBLOCK prevents the system from blocking for a long time.
	connection.f, err = os.OpenFile(connection.Port,
		syscall.O_RDWR|syscall.O_NOCTTY|syscall.O_NONBLOCK, 0666)
	if err != nil {
		return err
	}

	// Close the file on error occurrence.
	defer func() {
		if err != nil && connection.f != nil {
			connection.f.Close()
		}
	}()

	// Create a plain termios, which allows the program to execute
	// input/output operations.
	termios := syscall.Termios{}

	// Setup the baud rate in the termios structure.
	baudrate := baudrates[connection.Baud]

	termios.Cflag |= baudrate
	termios.Ispeed = baudrate
	termios.Ospeed = baudrate

	// Setup stop bits in the termios structure.
	switch connection.StopBit {
	case StopBit1:
		termios.Cflag &^= syscall.CSTOPB // CSTOPB = 0x40
	case StopBit2:
		termios.Cflag |= syscall.CSTOPB
	default:
		return errStopBit
	}

	// Setup data bits in the termios structure.
	databit := databits[connection.DataBit]
	termios.Cflag |= databit

	// Setup parity in the termios structure.
	switch connection.Parity {
	case ParityNone:
		termios.Cflag &^= syscall.PARENB // PARENB = 0x100
	case ParityEven:
		termios.Cflag |= syscall.PARENB
	case ParityOdd:
		termios.Cflag |= syscall.PARENB
		termios.Cflag |= syscall.PARODD // PARODD = 0x200
	default:
		return errParity
	}

	// // set blocking / non-blocking read
	vmin := uint8(0)
	if timeout == 0 {
		vmin = 1
	}

	// Attach min bytes and timeout to the termios structure.
	termios.Cc = [32]uint8{
		syscall.VMIN:  vmin,    // min bytes per transfer
		syscall.VTIME: timeout, // actual read timeout in deciseconds
	}

	// Execute IOCTL with the modified termios structure to apply the changes.
	if _, _, errno := syscall.Syscall6(
		// device-specific input/output operations
		syscall.SYS_IOCTL,
		// open file descriptor
		uintptr(connection.f.Fd()),
		// a request code number to set the current serial port settings
		uintptr(syscall.TCSETS),
		//TODO: it looks like syscall.TCSETS is not available under
		// freebsd and darwin. Is this a bug?
		uintptr(unsafe.Pointer(&termios)), // a pointer to the termios structure
		0,
		0,
		0,
	); errno != 0 {
		return errno
	}

	connection.isOpen = true
	return nil
}