From mboxrd@z Thu Jan  1 00:00:00 1970
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Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!bbn!inmet!ishmael!inmet!stt
From: stt@inmet
Newsgroups: comp.lang.ada
Subject: Re: How do you read keystrokes in A
Message-ID: <124000045@inmet>
Date: 18 May 89 15:48:00 GMT
References: <6430002@hpcupt1.HP.COM>
Nf-ID: #R:hpcupt1.HP.COM:-643000200:inmet:124000045:000:923
Nf-From: inmet!stt    May 18 11:48:00 1989
List-Id: <comp.lang.ada>


They are called "representation clauses."
In particular, the one
to which you refer is an "address clause for an interrupt entry."

There are in fact a number of compilers which support interrupt entries.
However, the more critical issue is whether the operating
system provides an interface which gives non-kernel
code the chance to be informed when a key is typed.
Unix systems generally provide "signals" for
the Interrupt and Quit keys (often "^C" and "^\").
Getting a signal on any key is tougher.

For the purposes of the original question, "raw" or "cbreak"
mode would be adequate on Unix, but again, it depends
on whether the Ada run-time-system supports
these modes, or whether the user wants to "roll their own"
input routines (presumably using pragma Interface).

Similar capabilities exist in VMS, but
the same caveats apply (need support in RTS or roll-your-own).

Tucker Taft
Intermetrics, Inc.
Cambridge, MA