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

From: williamkempf_at_[hidden]
Date: 2001-08-03 08:34:34

--- In boost_at_y..., "Scott McCaskill" <scott_at_m...> wrote:
> > > 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.
> >
> 
> Yes, I'm also considering this.  It will work as long as the thread 
exits by
> some "normal" means, which it always should (i.e., by returning 
from the
> thread function, not because something called
> _endthreadex/pthread_exit/etc).  I just thought it would be a bit 
more
> robust if I could also get asynchronous notification in all cases.

I've considered including a thread::exit() routine, but don't expect 
one in the first release.  For now, calling such native methods would 
produce undefined behavior.

> > > 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?
> >
> 
> Right now it checks (polls) periodically to see if any have ended.  
I'm
> considering what the implications would be if I changed it to wait 
(block)
> until any thread ended.

Just curious, but what does it do if the poll indicates a thread has 
died?

Bill Kempf