[C++-sig] Re: problem using global variable, static variable

[David Abrahams]

Cyril Bonnard <cyril.bonnard at cirad.fr> writes:

> i have a problem defining global and static variables: the variable is
> not recognized
>
> this peace of code highlights the problem:
> test.h:
> class color
> {
> public:
>   color() : col(0) {}
>   ~color() {}
>  const static color BLACK;// error
>   //static color YELLOW;     // same error
>   //static int i;            // same error
>   int col;
> };
>
> test.cpp: In function `void init_module_test()':
> test.cpp:14: no matching function for call to
> boost::python::class_<color, boost::python::detail::not_specified,
> boost::python::detail::not_specified,
> boost::python::detail::not_specified>::def_readonly(const char[6],
> const color*)'
> scons: *** [test.os] Error

This should work now.  Please try the latest CVS.

> i try to reproduce this "behaviour" with a global variable using pyste:
>
> class color
> {
> public:
>   color() : col(0) {}
>   ~color() {}
>  //const static color BLACK;// error
>   //static color YELLOW;     // error
>   //static int i;            // error
>   int col;
> };
>
> static color BLACK;
>
> pyste generates code which seems very strange to me:
> BOOST_PYTHON_MODULE(test)
> {
>     class_< color >("color", init<  >())
>         .def(init< const color & >())
>         .def_readwrite("col", &color::col)
>     ;
>
>     def("_GLOBAL__D__home_cbonnard_devlp_AMAPmod_src_GEOM_test.hef3xme",
>     &_GLOBAL__D__home_cbonnard_devlp_AMAPmod_src_GEOM_test.hef3xme);
>     def("_GLOBAL__I__home_cbonnard_devlp_AMAPmod_src_GEOM_test.hp8ylhc",
>     &_GLOBAL__I__home_cbonnard_devlp_AMAPmod_src_GEOM_test.hp8ylhc);

This appears to be a Pyste bug.  It should say:

     scope().attr("BLACK") = BLACK;

> My questions are: how should i proceed to declare and use global and
> static variables? is the above pyste code known? how to resolve the
> problem?

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