Reviewed and revised April 2024
xcall ECHO {,channel}
xcall NOECHO {,channel}
ECHO is used to turn terminal echo on. It may also be used to return a serial port under UNIX to its normal settings. NOECHO is used to disable terminal echo.
Parameters
channel (Unsigned Int) [in]
Optional file channel associated with a serial point under UNIX. A value of zero, or omitted, refers to the terminal.
Calling ECHO with no arguments is equivalent to executing the ECHO statement.
Comments
NOECHO is usually used in conjunction with GET or some other subroutine for terminal input, such as INFLD, in order to (a) allow character input, and (b) disable echo. NOECHO does not affect the true state of the terminal, but merely changes the internal operation of A-Shell itself. So, for example, if HOSTEX is used to execute a host command, that command will function in the same way whether or not the NOECHO subroutine had been used.
Under Unix, a serial port may be opened for input, and then NOECHO called with that channel specified, for example:
open #1,"/dev/tty1",input
xcall NOECHO,1
In this case, the true host mode of the port will be changed. Echo will be disabled, cooked mode processing will be disabled and so on, enabling all characters to be received unaltered from the port with the GET routine. This is particularly useful for communicating with external equipment such as modems, time record devices and so on.
If a port’s mode is changed in this way, then it should be reset with NOECHO before closing the channel. Failure to do this will leave the port in its altered state even when A-Shell is exited.
Also See
| • | GET for more details on inputting from a serial port |
