The OnHandFlow event occurs when other application changes flow control parameters for virtual serial port.
Parameters:
- ControlHandShake [out] : ControlHandShake is a set of flags that defines the modem lines that are used for flow control. Can be combination of the following flags:
| Value | Meaning | Hex |
| SERIAL_DTR_CONTROL | Enables the DTR line when the device is opened and leaves it on. | 0x01 |
| SERIAL_DTR_HANDSHAKE | Use the modem signal DTR for input flow control. For the real serial port the DTR line is cleared by the controller if the receive buffer reaches the programmed high water mark. See also description of XonLimit and XoffLimit. | 0x02 |
| SERIAL_CTS_HANDSHAKE | Use the modem signal CTS, DCD or DSR respectively for output flow control. For the real serial port if the corresponding modem line(s) found as cleared, the controller will hold data transmission. | 0x08 |
| SERIAL_DCD_HANDSHAKE | 0x20 | |
| SERIAL_DSR_HANDSHAKE | 0x10 | |
| SERIAL_DSR_SENSITIVITY | Ignore any character arriving when the DSR line is not set. | 0x40 |
| SERIAL_ERROR_ABORT | If there exists an error condition the driver abort all read and writes to or from this port. | 0x80000000 |
- FlowReplace [out] : FlowReplace is a set of flags defining flow control stuff. Can be combination of the following flags:
| Value | Meaning | Hex |
| SERIAL_AUTO_TRANSMIT | Use the XON/XOFF protocol based flow control for output. | 0x01 |
| SERIAL_AUTO_RECEIVE | Use the XON/XOFF protocol based flow control for input. | 0x02 |
| SERIAL_ERROR_CHAR | If set, the ErrorChar is placed in the stream of received characters on error conditions like buffer overflow, frame errors and so on. | 0x04 |
| SERIAL_NULL_STRIPPING | If set, the reception of a NULL character is ignored. | 0x08 |
| SERIAL_BREAK_CHAR | If set, the BreakChar is placed in the stream of received characters when a break condition was detected. | 0x10 |
| SERIAL_RTS_CONTROL | Enables the RTS line when the device is opened and leaves it on. | 0x40 |
| SERIAL_RTS_HANDSHAKE | Use the modem signal RTS for input flow control. | 0x80 |
- XOnLimit [out] : Minimum number of bytes allowed in the input buffer before flow control is activated to inhibit the sender.
- XOffLimit [out] : Maximum number of bytes allowed in the input buffer before flow control is activated to allow transmission by the sender.
Tip: See also: OnBaudRate event, OnLineControl event, OnTimeouts event