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

From: Roland Schwarz (roland.schwarz_at_[hidden])
Date: 2007-03-26 17:03:48

Howard Hinnant wrote:
>     t.cancel() is the same as t.raise(std::thread_canceled)

But semantics of cancel is different, no?
Cancel is expected to bring the thread down, yes?

Not so raise, it just is sending kind of a signal to the thread.
(The slot being catch clause).

> Beman and Peter have been active in the area of propagating exceptions  
> from t back through the join.  You are the first (that I know of) to  
> suggest the generalized propagation the other way. :-)  Do you have  
> use cases other than: t.raise(std::thread_canceled)?  Any  
> implementation strategies?

I implemented a small prototype and used it already in an application.
I was not using exceptions at this time, as throwing the exceptions
I considered not the hard part. I was seeing this syntactic sugar at
that time. More interesting was how to establish the interruptible (or
"alertable") state.
Al though at that time I implemented it as a strict add on to
boost thread, because I just wanted to experiment with the usability
of the interface. It could be improved a lot I believe if it were
tighter integrated into boost:thread. (I needed to resort to
notify_all internally e.g, where the program logic would only demand
for notify_one.)
I uploaded it to the vault under a name "alertable thread" if my
memory is not fading...

Roland