pthread_cancel and EH: let's try this again

[David Abrahams]

Nathan Sidwell <nathan at codesourcery.com> writes:

> IMHO #1 is better, for it also allows us to say 'thread cancellation is
> *exactly* like exception handling'.

It's more than that.  #2 changes the exception handling model.
Simplicity of definition and programming model is crucial.  People
already have enough trouble coming to grips with exception safety.
Introducing #2 complicates the EH model, so I oppose it on those
grounds also.

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