Queries or sets the software handshake (automatic XON/XOFF)
[<cXOFFchar>]) --> lOldHandshake
<nComPort> Designates the port (1 to N) for which the software
handshake is set.
<lNewHandshake> Designates whether the handshake is on (.T.) or off
(.F.). If this parameter is omitted, the function returns the current
<cXONchar> Designates any character you choose as an XON character.
The default character is ASCII 19 - Ctrl-S.
<cXOFFchar> Designates any character you choose as an XOFF
character. The default value is ASCII 17 - Ctrl-Q.
The function returns the previously set value.
With modem connections, a hardware handshake is impossible, which is why
we are making a software handshake available with this function. When a
buffer is 75% full, an XOFF character (Ctrl-Q) is transmitted to the
remote station. As soon as the buffer has again been emptied to 50% or
less, the XON character (Ctrl-S) is transmitted. You can use characters
other than Ctrl-S or Ctrl-Q for individual protocols, which would then
be taken into account in the situations described above.
” The software handshake only supports background transmission
(when COM_OPEN() has been implemented with the third parameter
” When you want to transmit binary data, the software handshake
must always be turned off.
COM_OPEN(1, 1000, 1000) // Open port, background transmission
COM_SOFT(1, .T.) // Software handshake COM1