Re: [Boost-users] boost::python::import causes access violation

Subject: Re: [Boost-users] boost::python::import causes access violation
From: Dave Abrahams (dave_at_[hidden])
Date: 2011-02-08 12:08:36

At Fri, 4 Feb 2011 14:08:11 +0000,
Julian Bailey wrote:
> 
> Hi,
> 
> I am running through the basic examples on the boost website for embedding boost::python.
> 
> My code currently reads:
> 
> #include <iostream>
> 
> #include "./include/Python.h"
> #include "./boost/python.hpp"
> 
> using namespace boost::python;
> 
> int    main(void)
> {
>        Py_Initialize();
> 
>        object main_module = import("__main__");
>        object main_namespace = main_module.attr("__dict__");
> 
>        object ignored = exec("print Hello world",main_namespace);
> 
>        return 0;
> }
> 
> The program links successfully and begins running, however an access violation occurs (NULL pointer) at the first line after "py_initialize();" when i call import("__main__");

Do you have a complete stack backtrace?

> Visual studio 2010s debugger says the exception occurs at:  line 74 in object_attributes.hpp:
> 
> inline object const_attribute_policies::get(object const& target, char const* key)
> {
>     return python::getattr(target, key);
> }
> 
> 
> Python was built using Visual studio 2010 so i had access to the python debug
> library. 

Yeah, but you can't use the python debug library unless you are also passing
python-debugging=on to your Boost build as described in
http://www.boost.org/doc/libs/1_45_0/libs/python/doc/building.html#python-debugging-builds
.  Are you doing that?  If not, a crash is to be expected.

> Boost is version 1.45 and was built using :
> 
> bjam --build-type=complete msvc stage --with-python
> 
> I am linking against:
> boost_python-vc100-mt-gd-1_45.lib
> and
> boost_python-vc100-mt-gd-1_45.dll
> 
> I have looked for soutions on the internet and have found nothing right now. Can anyone help me?
> 
> note: i am building my application in MSVC 2010, this should work though shouldn't it?

It should.

-- 
Dave Abrahams
BoostPro Computing
http://www.boostpro.com