Re: first sight

From: bill_kempf (williamkempf_at_[hidden])
Date: 2002-01-15 12:23:35

--- In boost_at_y..., Lee Brown <lee_at_a...> wrote:
> 
> > (C) is the biggest issue.  The thread_ref you refer to below 
failed
> > in this regard.  Cancellation requests should really cause instant
> > cancellation during such blocking operations.  However, doing 
this in
> > a portable manner, especially one that doesn't add overhead to 
such
> > operations, is very difficult to do.
> 
> The only way to do this (UNIX) is by sending the thread a signal.

Not true.  All that would be required is to have the Boost 
synchronization primitives built on top of a complex condition 
variable that can watch both the state it's interested in (such as a 
mutex being unlocked) and for a cancellation request.  Trivial to 
implement, but it means severe overhead on all synchronization 
operations.

I'm sure there are other solutions as well, but none are both 
efficient and easily portable.

There's likely no solution for C, and Boost.Threads may well have to 
ignore this issue.  But I'm not ready to give up with out a fight ;).

Bill Kempf