Re: [boost] [statechart] threading-related failures

From: Andreas Huber (ahd6974-spamgroupstrap_at_[hidden])
Date: 2006-11-27 07:47:35

Hi Volodya

Vladimir Prus wrote:
> There are some fresh statechart failures:
>
>   http://tinyurl.com/wsdcj
>
> The seem to be related to my change to Boost.Build, that makes it
> (correctly) set threading=multi on msvc, on the grounds that it
> always uses multi-threading with shared runtime.

I've noticed the failures yesterday but have been unsure whether they
were due to my adjustments last week or not.

> The comments in libs/statechart/test/Jamfile.v2 say:
>
> # Some platforms have either problems with the automatic detection of
> the # threading mode (e.g. vc-7_1 & gcc >= 3.4.0) or don't support
> single- # threaded mode (e.g. vc-8_0). We therefore manually turn MT
> off here
> local st-requirements = <define>BOOST_DISABLE_THREADS ;
>
> for local cpp-source in $(cpp-sources)
>  {
>    obj $(name)$(cpp-source)
>      : $(cpp-source).cpp
>      : <threading>single:$(st-requirements) $(requirements) ;
>    objs += $(name)$(cpp-source) ;
>  }

I guess I need to give a bit of background here: As far as I understand,
including config.hpp into a cpp that is compiled with a <threading>multi
requirement should lead to the definition of BOOST_HAS_THREADS. Vice
versa, BOOST_HAS_THREADS is not defined for cpps that are compiled with
a <threading>single requirement. The comment in the jamfile attempts to
explain that this automatism does not natively work on a few platforms.
The idea behind <threading>single:$(st-requirements) was an attempt to
fix this problem.

> I think the right fix *might be* changing <threading>single above to
> <threading>multi, *or* adding
>
>       <threading>multi:$(st-requirements)
>
> or making $(st-requirements) unconditional. Unfortunately, I'm not
> sure
> which one is right, and the comment above does not help me.

The idea was that only the tests that absolutely need to run in MT mode
actually link against the treading library. I'll therefore make
$(st-requirements) unconditional for those tests.

Question: Should I still specify a <threading>single requirement for 
those tests or would that lead to some sort of conflict (because e.g. 
vc-8.0 is always <threading>multi).

Thanks & Regards,

-- 
Andreas Huber
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