Re: [boost] Building ThreadPool with boost::function in boost::lockfree::queue

Subject: Re: [boost] Building ThreadPool with boost::function in boost::lockfree::queue
From: Ryan Fogarty (ryan.fogarty.msece_at_[hidden])
Date: 2013-04-01 15:01:24

On Mon, Apr 1, 2013 at 11:51 AM, Tim Blechmann <tim_at_[hidden]> wrote:

> > In file included from TestFunctionCompleteness.cpp:11:0:
> > /usr/local/boost_1_53_0/include/boost/lockfree/queue.hpp: In
> instantiation
> > of ‘class boost::lockfree::queue<boost::function<void()> >’:
> > TestFunctionCompleteness.cpp:42:17:   required from here
> > /usr/local/boost_1_53_0/include/boost/lockfree/queue.hpp:79:5: error:
> > static assertion failed: (boost::has_trivial_destructor<T>::value)
> > /usr/local/boost_1_53_0/include/boost/lockfree/queue.hpp:83:5: error:
> > static assertion failed: (boost::has_trivial_assign<T>::value)
> >
> >
> > Is boost::function somehow an incomplete type and not expected to work in
> > boost::lockfree::queue or is this a bug in the queue implementation? Can
> > anyone suggest a simple workaround?
>
> as the error message implies: boost::function is not trivially
> assignable and does not have a trivial destructor. so it cannot be used
> with boost::lockfree::queue.
>
> possible workaround: use a functor that meets these requirements
>
> hth, tim
>

Thanks Tim,

   I missed those restrictive requirements for queue. I just read your
responses here (
http://boost.2283326.n4.nabble.com/lockfree-crash-in-queue-td4641709.html)
to another fellow and it looks like he was trying to build something almost
exactly like what I was trying to do. I guess the implication is that
lockfree::queue can't contain anything that is heap allocated (job functor
with data that requires handle) and still use safe C++ practices via a
handle idiom/RAII. That's too bad. If technically possible I would love to
see something like the concurrent_queue from TBB incorporated in your lib
(of course then it is relaxing the lockfree-ness of the data structure a
bit). TBB or a wrapped/synchronized deque will work well enough for me for
now.
   If I am missing something trivial on how to preserve RAII between
producer and consumer(s) threads while messaging through your queue please
let me know!

Thanks,
Ryan