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From: dewar@merv.cs.nyu.edu (Robert Dewar)
Subject: Re: CRC in Ada?
Date: 1997/03/22
Message-ID: <dewar.859061575@merv>#1/1
X-Deja-AN: 227583594
References: <1997Mar2.220652@nova.wright.edu>
 <331bf6ce.2832564@news.logica.co.uk> <dewar.857509168@merv>
 <332B5EBD.3D9E@worldnet.att.net> <dewar.858525008@merv>
 <332C9185.61C1@worldnet.att.net> <dewar.858568547@merv>
 <332F5CC8.6D7C@worldnet.att.net> <dewar.858769863@merv>
 <33320957.B@worldnet.att.net> <33344C9C.542F@us.net>
Organization: New York University
Newsgroups: comp.lang.ada
Date: 1997-03-22T00:00:00+00:00
List-Id: <comp.lang.ada>


i<<IMHO Stream_Io may be more appropriate if available. If not
sequential_io is a logical choice unfortunately you have a correct but
inefficient implementation to use.>>

Logical is not quite the word I would use, since logic says that there
is no reason to expect that it would work at all, since the RM neither
states, nor even implies that it will work. Indeed by pointing out that
type checking *may* be done, the RM puts you on notice that it may well
not work.

Pragmatically, if, for some reason, you think it is better to write
dubious non-portable Ada code, as opposed to portable code that uses
pragma interface to an ANSI C routine, then it may be the case in Ada 83
that sequential_io is your only choice, but logical, I think not!

Also, note that in your hacking of the sequential IO package, you may
well have introduced tasking non-safety. Any time you add more state
(in this case the buffer and its pointers), you risk task safety,
and you need to at least think about this as an issue.