Re: [boost] Graph library concept check problem

From: Matthias Troyer (troyer_at_[hidden])
Date: 2006-04-28 20:24:54

On Apr 28, 2006, at 4:54 PM, Daniel Walker wrote:

> On 4/28/06, Matthias Troyer <troyer_at_[hidden]> wrote:
>> Hi,
>>
>> Trying to compile our ALPS project sources (http://alps.comp-
>> phys.org) with the CVS HEAD I encountered a number of problems with
>> the BGL concept checking. In particular on MacOS X, using the  
>> Apple g+
>> + 4.0.1, I encounter problems in depth_first_search.hpp with:
>>
>> Matthias
>
> I don't believe models of the Graph or DFSVisitor concepts are
> required to be default constructable.
>
> I tried to take a look at this compiling ALPS-1.3a1, but couldn't
> reproduce the error with g++ 4.0.3 on Linux. As far as I can tell
> neither DFSVisitorConcept nor CopyConstructibleConcept use a default
> constructor. However, if for some reason your (custom) visitor class
> tries to default construct a graph in a member function
> (initialize_vertex(), start_vertex(), etc.) this could cause the
> error. Could you give a specific example of code that causes the
> error?

I saw the same problem also in other libraries now and it seems to be  
an issue with concept checking in general on my machine. The default  
constructors of all data members of the concept checking classes seem  
to get instantiated somehow. I'll try to track this down.

Matthias