Re: [boost] python linking problem

From: David Abrahams (david.abrahams_at_[hidden])
Date: 2001-10-18 07:33:30

IIRC we've seen this problem before and it's a known VC6 bug without a known
workaround... Sorry!

===================================================
  David Abrahams, C++ library designer for hire
 resume: http://users.rcn.com/abrahams/resume.html

        C++ Booster (http://www.boost.org)
          email: david.abrahams_at_[hidden]
===================================================

----- Original Message -----
From: <Drew.Whitehouse_at_[hidden]>

>
> Under VC6 I have a strange linking problem - if the specified line is
> uncommented things work, otherwise I see the error -
>
>   Creating library Debug/_alchemy_d.lib and object
> Debug/_alchemy_d.exp
> _alchemy.obj : error LNK2001: unresolved external symbol "class
> `anonymous namespace'::hello & __cdecl from_python(struct _object
> *,struct boost::python::type<class `anonymous namespace'::hello &>)"
> (?from_python@@YAAAVhello@?%D:\home\drw900\Project
> s\pyAlchemy\SRC\boostAlchemy\_alchemy.cpp204027573@@PAU_object@@U?
> $type_at_AAVhello@?%D:\home\drw900
> \Projects\pyAlchemy\SRC\boostAlchemy\_alchemy.cpp204027573@@@python_at_bo
> ost@@@Z)
> _alchemy_d.pyd : fatal error LNK1120: 1 unresolved externals
> Error executing link.exe.
>
> _alchemy_d.pyd - 2 error(s), 0 warning(s)
>
> The code is -
>
> #include <iostream>
> #include <string>
> namespace
> {
>   class hello
>   {
>   public:
>     hello() { this->country = "none"; }
>     void foo() const { std::cerr << "Hello from " + country; }
>     std::string greet() const { return "Hello from " + country; }
>   private:
>     std::string country;
>   };
> }
>
> #include <boost/python/class_builder.hpp>
> namespace python = boost::python;
> BOOST_PYTHON_MODULE_INIT(_alchemy)
> {
>   try
>   {
>     python::module_builder this_module("_alchemy");
>     python::class_builder<hello> hello_class(this_module, "hello");
>     hello_class.def(python::constructor<>());
>     hello_class.def(&hello::foo, "foo");
>     // module links if the next line uncommented.....
>     file://hello_class.def(&hello::greet, "greet");
>   }
>   catch(...)
>   {
>     python::handle_exception(); // Deal with the exception for Python
>   }
> }
>
>
>
>
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