boost.threads [was RE: [boost] Re: sockets /network programming Requirements]

From: williamkempf_at_[hidden]
Date: 2001-08-02 17:21:13

--- In boost_at_y..., "Scott McCaskill" <scott_at_m...> wrote:
> > --- In boost_at_y..., "Scott McCaskill" <scott_at_m...> wrote:
> > > I'd like to read the documentation/proposal for Boost.Threads 
(or
> > source, or
> > > any description)--where can I find it?  The archives indicate 
that
> > at one
> > > time there was a file in the threads directory on yahoo called
> > threads2.zip,
> > > but it is gone, and there doesn't seem to be anything in CVS 
either.
> >
> > It does exist in CVS, but on a branch instead of part of the main
> > distribution.  Check out the branch threads-initial.  Note, 
however,
> > that the code and documentation are both currently under frequent 
and
> > extensive modifications in preperation of formal submission.
> >
> > Bill Kempf
> >
> 
> Thanks, got it.  I've been perusing the source quite intently and 
so far I
> really like what I see.  I also have a question.  I have an 
application that
> creates several threads and I want the main thread to be able to 
find out if
> any of the created threads have died.  It appears that I could do 
this using
> boost::thread::try_join() on each of the created threads, but is 
there (or
> will there be) a better way?  Currently, the app is using
> WaitForMultipleObjects() to do this.

The Wait* operations in Win32 threading are both extremely nice, and 
a major pain.  Boost.Threads doesn't directly support any concepts 
similar to WaitForMultipleObjects (other than 
thread_group::join_all).  However, it's not difficult to do what you 
want here using a condition variable, though this requires support 
from the threads which will have to notify_one/all() the condition.

> I realize that this is probably just an optimization, but it feels 
strange
> to have to poll to find out if a thread has ended.

Are you _trying_ to find out if a thread has ended, or waiting until 
any thread has ended?  In other words, is the wait a blocking 
operation?

> Thanks,
> scott
> 
> P.S.-- I also spotted an apparent infinite loop in the code:
> 
> bool thread::operator!=(const thread& other) const
> {
>     return operator!=(other);
> }
> 
> That should be !operator==(other), no?

Oops.  Yep.  Nasty typo on my part.  Thanks for catching that.

Bill Kempf