Re: [boost] Boost.Threads, N2178, N2184, et al

From: David Abrahams (dave_at_[hidden])
Date: 2007-03-26 19:16:56

on Mon Mar 26 2007, Roland Schwarz <roland.schwarz-AT-chello.at> wrote:

> What I really meant by "do we need cancellation" is the inherent
> meaning of cancellation: once started you can't stop it.

That's not inherent.  You're stepping into a minefield here...

> Your example seems to imply this, but I don't think this
> necessarily is the case.

"Everybody" in the C++ community wants cancellation to be an ordinary,
stoppable, C++ exception, thrown only synchronously, at well-defined
cancellation points.  Anything else makes writing cancellation-safe
code basically untenable.  In fact, the only person I know of in *any*
community who insists that cancellation must be unstoppable is Ullrich
Drepper.

> Another point (not a strict technical one though): Developing a
> mechanism that could be used for cancellation but strictly speaking
> _is_ _not_ cancellation could end the stalling discussions about
> cancellation, which are lasting almost forever now.

I suggest that trying to use meanings of "cancellation" other than the
one(s) used in the pthread standard at this point can only confuse
things, which hardly seems like a way to un-stall the process.

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com