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From: gwalker@SPCA.BBN.COM (Gail Rubin Walker)
Newsgroups: comp.os.vms
Subject: Re:  How to get multi-level command history to work?
Message-ID: <8706252141.AA27309@ucbvax.Berkeley.EDU>
Date: Wed, 24-Jun-87 09:20:59 EDT
Article-I.D.: ucbvax.8706252141.AA27309
Posted: Wed Jun 24 09:20:59 1987
Date-Received: Sat, 27-Jun-87 04:26:02 EDT
Sender: daemon@ucbvax.BERKELEY.EDU
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It probably hasn't been discussed before because it IS documented and
has been from the start. See the Terminal Drivers chapter of the
I/O Manual. I implemented 20 line recall in a program myself a few years
ago using only that documentation - no fiche reading. You get
to use a new (in VMS 4.0) form of $QIO read called an itemlist read and
you specify that you don't want the driver to do command line recall. Then
your program gets control when the user types up-arrow or ctrl-B (the terminator
returned to your program is ctrl-B whether they typed that or the up-arrow).
There is also a way to pre-fill the input (with a recalled line, for example).

The one thing I would caution you on - if you are modifying the input done
by existing programs, note that itemlist $QIOs have a different form of
I/O status block (IOSB) and the form IS also documented so be sure to check
your code if you use the IOSB.

-- Gail Walker, BBN