Re: [Boost-users] boost::thread::join causes assertion (pthreads)

From: Caleb Epstein (caleb.epstein_at_[hidden])
Date: 2005-03-23 21:25:21

On Thu, 24 Mar 2005 01:29:57 +0200, Peter Dimov <pdimov_at_[hidden]> wrote:
> Caleb Epstein wrote:
> > Even if the underlying implementation thread is not (e.g. it has been
> > pthread_detach'd or the equivalent)?  Or are you suggesting that a
> > join on a non-implementation-joinable thread should just succeed
> > silently?
> 
> Succeed silently, yes. That's what join means: wait for the thread to
> finish. If it has already finished, join should just return immediately. Not
> only that, it should be safe to call it from multiple threads at the same
> time, which should result in exactly one call to pthread_join.

But what of the case of a detached thread that is still running? 
These are not joinable, and having join succeed for them would be
misleading to the user, no?  Or does a user who tries to join a
detached thread get what s/he deserves?

> pthread_join is join+destructor rolled into one, but we have "real"
> destructors in C++, so we don't need to emulate its behavior so strictly.

Yes, but I'd expect that if I successfully join a thread, that the
thread would have well and truly stopped executing.  I don't think
there is any way to do that w/a detached pthread.

-- 
Caleb Epstein
caleb dot epstein at gmail dot com