Chapter 6 Typeahead Mode

Table of Contents

Effective with Release A.20.00, a typeahead capability is supported for use on MPE/iX systems. Typeahead makes it possible for a user at a terminal to enter data before the read which will accept that data is actually posted. This is especially convenient when you need to enter a series of commands with system processing delays in between.

The typeahead facility is controlled programmatically through the FDEVICECONTROL intrinsic, using one of three control directives. This chapter explains each of these typeahead controls, and provides code samples demonstrating how you can do the following:

Control whether or not typeahead is enabled at a terminal.
Bypass the typeahead buffer and take data for the next read directly from a terminal device.
Flush all information from the typeahead buffer before starting the next read.




	NOTE: DTC Telnet typeahead is operational only when single echo is enabled. Use FDEVICECONTROL with `controlcode` value 192 and `parm1` value 63, or the TTUTIL program, to enable single echo. PAD typeahead is operational only when `initial echo` is disabled. Use FDEVICECONTROL with `controlcode` value 192 and `parm1` value 4, FCONTROL(13), or the TTUTIL program to disable `initial echo`.

Chapter 6 Typeahead Mode

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