Subject: Re: [boost] [BGL] Visual Studio 12 finish_edge() failure, general BOOST_TTI_HAS_MEMBER_FUNCTION failure?
From: Michael Behrns-Miller (m_at_[hidden])
Date: 2014-04-01 16:12:06
On 4/1/2014 8:45 AM, Edward Diener wrote:
> On 4/1/2014 4:50 AM, Michael Behrns-Miller wrote:
>> On 4/1/2014 4:40 AM, Michael Behrns-Miller wrote:
>>> On 3/31/2014 6:30 PM, Edward Diener wrote:
>>>> On 3/31/2014 1:27 PM, Michael Behrns-Miller wrote:
>>>>> ...
>>>>> Here's how BGL defines it:
>>>>>
>>>>> -------------
>>>>>
>>>>> BOOST_TTI_HAS_MEMBER_FUNCTION(finish_edge)
>>>>>
>>>>> template <bool IsCallable> struct do_call_finish_edge {
>>>>> template <typename E, typename G, typename Vis>
>>>>> static void call_finish_edge(Vis& vis, const E& e, const G&
>>>>> g) {
>>>>> vis.finish_edge(e, g);
>>>>> }
>>>>> };
>>>>>
>>>>> template <> struct do_call_finish_edge<false> {
>>>>> template <typename E, typename G, typename Vis>
>>>>> static void call_finish_edge(Vis&, const E&, const G&) {}
>>>>> };
>>>>>
>>>>> template <typename E, typename G, typename Vis>
>>>>> void call_finish_edge(Vis& vis, const E& e, const G& g) { //
>>>>> Only
>>>>> call if method exists
>>>>> do_call_finish_edge<has_member_function_finish_edge<Vis,
>>>>> void>::value>::call_finish_edge(vis, e, g);
>>>>> }
>>>>
>>>> The invocation of has_member_function_finish_edge has to match the
>>>> member function signature which you are invoking. If the member
>>>> function signature for finish_edge is:
>>>>
>>>> void finish_edge(const E&, const G&);
>>>>
>>>> then your invocation for do_call_finish_edge must be:
>>>>
>>>> do_call_finish_edge
>>>> <
>>>> has_member_function_finish_edge
>>>> <
>>>> Vis,
>>>> void,
>>>> boost::mpl::vector
>>>> <
>>>> const E&,
>>>> const G&
>>>> >
>>>> >
>>>> ::value
>>>> >::call_finish_edge(vis, e, g);
>>>>
>>>> or
>>>>
>>>> do_call_finish_edge
>>>> <
>>>> has_member_function_finish_edge
>>>> <
>>>> void Vis::* (const E&,const G&)
>>>> >
>>>> ::value
>>>> >::call_finish_edge(vis, e, g);
>>>>
>>>>
>>>> _______________________________________________
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>>>
>>> Thank you Edward.
>>>
>>> The instantiation code was not mine, that is what is done by the BGL,
>>> here:
>>>
>>> boost\graph\depth_first_search.hpp
>>>
>>> The instantiation code does not seem to match your recommendation.
>>> This simple DFS test fails:
>>>
>>> https://svn.boost.org/trac/boost/attachment/ticket/9770/test.cc
>>>
>>> So it sounds like BGL needs some patching to match your format. It
>>> should change from...
>>>
>>> do_call_finish_edge<has_member_function_finish_edge<Vis,
>>> void>::value>::call_finish_edge(vis, e, g);
>>>
>>> to...
>>>
>>> do_call_finish_edge<has_member_function_finish_edge<void Vis::* (const
>>> E&,const G&)>::value>::call_finish_edge(vis, e, g);
>>>
>>> Does that sound correct?
>>
>> On the newer code, Visual Studio 12 gives me:
>>
>> boost_1_55_0/boost/graph/depth_first_search.hpp(86): error C2182:
>> 'abstract declarator' : illegal use of type 'void'
>
> I am the developer for TTI. In your test case the actual VIZ struct
> has templated member functions, so I do not think has_member_function
> will find your templated functions. TTI is a compile-time mechanism
> for producing compile-time code. But even if it does not find the
> member functions at compile-time TTI should not produce a compile-time
> error so I definitely want to look at this situation.
>
> As to why Visual Studio 12 gives that error I need to be able to
> reproduce your compile steps. I am an absolute novice with the Boost
> graph library. I think I need to build the library first, then run
> your test against it.
>
> Jeremiah Willcock produced the changes in graph using TTI so he may
> have had a very good reason for using the original has_member_function
> signature, although it looks wrong to me on purely a TTI basis.
> Hopefully he will chime in on his change.
>
>
>
> _______________________________________________
> Unsubscribe & other changes:
> http://listarchives.boost.org/mailman/listinfo.cgi/boost
Thanks Edward, appreciate the feedback, I'll be monitoring. In the
meantime my workaround of making finish_edge() non-optional is working
for me. But of course I'd prefer not to have to change boost code
before using. :-)
Sure appreciate all you guys do to develop and maintain the libraries,
boost is just fantastic.