Re: [boost] [Python] VC++ 7.1 workaround needed in boost/python/class.hpp

From: David Abrahams (dave_at_[hidden])
Date: 2005-11-22 11:29:38

Douglas Gregor <doug.gregor_at_[hidden]> writes:

> I'm running into problems with Visual C++ 7.1 and  
> class_<..>::add_property() in Boost.Python. The issue pops up in this  
> bit o' code:
>
>     class_<Graph> graph(name);
>     graph
>          .add_property("vertex_properties",  
> &py_get_vertex_properties<Graph>,
>            "A Python dictionary mapping from vertex property names to\n"
>            "property maps. These properties are \"attached\" to the  
> graph\n"
>            "and will be pickled or serialized along with the graph.")
>          .add_property("edge_properties",  
> &py_get_edge_properties<Graph>,
>            "A Python dictionary mapping from edge property names to\n"
>            "property maps. These properties are \"attached\" to the  
> graph\n"
>            "and will be pickled or serialized along with the graph.")
>
> In particular, the compiler chokes when instantiating add_property(),  
> because it can't tell that the third parameter is a docstring  
> (instead of a setter). At line 304 of boost/python/class.hpp  
> (RC_1_33_0 branch), there is a workaround for all Visual C++ versions  
> prior to 7.1 that avoids this problem: if I switch the "1300" to  
> "1310" to include VC++ 7.1, everything works fine.
>
> Unfortunately, I wasn't able to create a small test case that  
> exhibits the problem. 

Can you add test case that's just large enough to reproduce it to one
of the Boost.Python regression tests?

> If you really, really want to reproduce the  
> problem, you can grab the BGL-Python bindings that triggered it with:
>
> 	svn co https://svn.osl.iu.edu/svn/projects/viz/bgl-python
>
> Should we do the version bump in the workaround, or could that cause  
> problems?

Go ahead and bump the version; we'll see tests fail if there are any
problems.  However, I'd most like to see a test fail before you make
the change ;-)

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com