SetRealPortHandflow

The SetRealPortHandflow method

The SetRealPortHandflow method sets the configuration of handshake flow control of real serial port.  

BOOL SetHandFlow(
ULONG ControlHandShake,// Handshake control parameter
ULONG ,// Flow control parameter
ULONG XOnLimit,// Flow control parameter
ULONG XOffLimit 
);

Parameters
ControlHandShake – [out] ControlHandShake is a set of flags that defines the modem lines that are used for flow control. Can be the  combination of the following flags:

ValueMeaningHex
SERIAL_DTR_CONTROLEnables the DTR line when the device is opened and leaves it on.0x01
SERIAL_DTR_HANDSHAKEUse 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_HANDSHAKEUse 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_HANDSHAKE0x20
SERIAL_DSR_HANDSHAKE0x10
SERIAL_DSR_SENSITIVITYIgnore any character arriving when the DSR line is not set.0x40
SERIAL_ERROR_ABORTIf there exists an error condition the driver aborts all read and writes to or from
this port.
0x80000000

FlowReplace – [out] FlowReplace is a set of flags defining flow control stuff. Can be the combination of the following flags:

ValueMeaningHex
SERIAL_AUTO_TRANSMITUse the XON/XOFF protocol based flow control for output.0x01
SERIAL_AUTO_RECEIVEUse the XON/XOFF protocol based flow control for input.0x02
SERIAL_ERROR_CHARIf 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_STRIPPINGIf set, the reception of a NULL character is ignored.0x08
SERIAL_BREAK_CHARIf set, the BreakChar is placed in the stream of received characters when a
break condition was detected.
0x10
SERIAL_RTS_CONTROLEnables the RTS line when the device is opened and leaves it on.0x40
SERIAL_RTS_HANDSHAKEUse 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.

Return Values
If the function succeeds, the return value is TRUE, otherwise FALSE.

Remarks
You can set this method forcibly, without waiting for events.