[cpp-threads] RE: "Agenda" for august 23-25 concurrency meeting

[Herb Sutter]

Thanks, Nick. In your latest below, I'm confused by the "of kind X" and "two different kinds of object" parts. Can you clarify? Transitivity in the examples shown earlier have to hold even when x and y are of different types -- or is this not what you meant?

Herb



> -----Original Message-----
> From: cpp-threads-bounces at decadentplace.org.uk [mailto:cpp-threads-
> bounces at decadentplace.org.uk] On Behalf Of Nick Maclaren
> Sent: Sunday, September 03, 2006 3:40 AM
> To: C++ threads standardisation
> Cc: c++std-ext at accu.org; Bronis R. Supinski; David Miller; Lawrence Crowl;
> omp-lang at openmp.org; Terrence.Miller at sun.com; David Miller; Howard
> Hinnant; Bill Seymour; P.J. Plauger (Dinkumware Ltd); Bjarne Stroustrup;
> Meredith, Alisdair; Eric Niebler; Pete Becker
> Subject: Re: [cpp-threads] RE: "Agenda" for august 23-25 concurrency
> meeting
>
> I humbly apologise to Herb for maligning his terminology!
>
> I had been following only the NON-lock postings, as I thought that we
> had settled the lock matter, and so thought that we were talking about
> the other issue!  To summarise my views, here they are:
>
> I agree with Herb and others that transitivity is essential, and that
> anything that has release/acquire semantics on objects of kind X should
> imply full transitivity on ALL objects of kind X.  As I posted, I have
> written code that had only pairwise semantics (message passing) and had
> major difficulties in handling globally shared/updatable objects.
>
> But we need to be very careful that we don't confuse this with the
> associated concept of when two transitive relations are consistent.
> I know that I have significant problems handling two transitivity
> graphs in my head at one time, but unfortunately that is the way that
> we have to work when handling two different kinds of object.
>
> This won't be the last time that I get confused :-(
>
>
> Regards,
> Nick Maclaren,
> University of Cambridge Computing Service,
> New Museums Site, Pembroke Street, Cambridge CB2 3QH, England.
> Email:  nmm1 at cam.ac.uk
> Tel.:  +44 1223 334761    Fax:  +44 1223 334679
>
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