Re: [Boost-users] [thread] Is a call to interrupt_all blocking?

Subject: Re: [Boost-users] [thread] Is a call to interrupt_all blocking?
From: Sachin Garg (schngrg_at_[hidden])
Date: 2010-01-27 07:24:25

On Tue, Jan 26, 2010 at 4:22 PM, Anthony Williams <anthony.ajw_at_[hidden]> wrote:
> Sachin Garg <schngrg_at_[hidden]> writes:
>
> > Does a call to interrupt_all blocks the calling thread, waiting for all threads
> > to be interrupted? Or is it supposed to return immediately and let the threads
> > hit their interruption points later?
>
> interrupt_all is not blocking.

My blocking problem seems to be because I am calling interrupt_all
when another thread is already waiting on a join_all for same
thread_group. Similar to the issue described in the post below. I am
using boost 1.39.0, is this fixed in current 1.41.0?

  http://lists.boost.org/boost-users/2009/10/53107.php

> However, there is currently a bug in
> interruption on pthreads which means threads can miss interruptions if
> they get a spurious condition variable wake at the wrong time. Since
> interruption causes spurious wakes for other threads waiting on the same
> cv this is particularly a problem for interrupt_all.

I think I can live with this bug for a while :-) let me know if I am
misunderstanding it.

The condition variable bug *seems* to mean that in worst case a thread
a may miss one interruption point and then get interrupted at its next
interruption point (the interruption is not lost, just delayed)

This will be ok in my application as missing an interruption is not
fatal and it does not cause any deadlocks etc (the thread will surely
reach its next interruption point soon and then get interrupted).

Is the fix for this expected in 1.42.0? 1.42.0 release seems to be
very close. Anyway, if my understanding of bug is correct, I can live
with it for a while.

Thanks for your help.

SG