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Re: volatile [was: GCC warnings for unused global variables]
- From: Michael Eager <eager at eagercon dot com>
- To: Mike Stump <mrs at apple dot com>
- Cc: Fergus Henderson <fjh at cs dot mu dot OZ dot AU>, Richard Henderson <rth at redhat dot com>, Geoff Keating <geoffk at geoffk dot org>, jbuck at synopsys dot com, espie at quatramaran dot ens dot fr, gcc at gcc dot gnu dot org
- Date: Thu, 08 May 2003 08:53:41 -0700
- Subject: Re: volatile [was: GCC warnings for unused global variables]
- References: <FA90BFE9-80E1-11D7-BD07-003065A77310@apple.com>
Mike Stump wrote:
On Saturday, May 3, 2003, at 09:50 AM, Michael Eager wrote:
When I was on the C++ Standards Committee, I submitted a proposal which
was intended to make volatile well defined and explicit, rather than
use the
vague definition inherited from C. Unfortunately, the proposal was not
adopted. A large part of the committee felt that volatile was an obscure
feature which did not need clarification. The small part of the
committee
which thought that volatile was important had the opinion that it
would be
impossible (or at least very difficult) to define it precisely,
although it
appeared that we all agreed on the same correct behavior for volatile.
Hum. My memory could be fading here, but I thought I was against it
because there was at least one wrong thing (IMHO) in how you defined it
at the time, and I thought the status quo was better than a status wrong.
I don't recall any specific suggestions for changes to the proposal, but
then again, this was a while ago. I withdrew the proposal when it became
apparent that there was limited interest in working out any differences.
The status quo is that volatile is not defined.
As I've said, there seems to be many opinions about what volatile means.
I'm sure that any proposal attempting to define volatile would generate
significant discussion. I'm not sure that it would be possible to arrive
at a consensus, though.
Anyway, I think it would be great if you'd put up your work on volatile
up on a web site, and solicit feedback, and fix/expand/explain it for
folks. If the nits of it are fixed, I think it would be good to have in
the language standards for C/C++. Also, we can link it from the gcc web
site for those that would like a more complete explanation of volatile.
I don't know whether I still have the proposal. I'll see if I can do this.
--
Michael Eager Eager Consulting eager@eagercon.com
1960 Park Blvd., Palo Alto, CA 94306 650-325-8077