[C++-sig] PyFinalize Safety

[Paul Guse]

> Stefan wrote:
>> Not sure if this solution/hack will work for you, but a quasi way to
>> reinitialize the interpreter is to clear the main dictionary to the 
>> original
>> state:
>>
>>     - make a copy of the main dictionary upon initialization
>>     - run your python script
>>     - clear the main dictionary
>>     - set the dictionary to the original copy.
>
> When reading the original posting I wondered about the reason for wanting 
> to
> reinitialize the python runtime. Your reply makes me even more curious.
>
> What do you mean by the 'main dictionary' ? Each call to 
> boost::python::exec_file
> can take a new dictionary, making the individual invocations completely 
> independent,
> can't it ?
>

By main dictionary I mean the "__dict__" attribute to the main module.
Checking the documentation, exec/exec_file  seems like the way to go, 
however, I can't actually find exec.hpp or import.hpp in my boost build. I'm 
using 1_33_1 and used the installer(win) from boost.consulting. Any thoughts 
on why I would not have those 2 headers? Newer version? My version of 
python.hpp does not include those files as well. Is this a new feature?

The solution I proposed came about due to the main module namespace 
retaining enties in it's _dict_ upon successive sessions (embeded).
So if I run the example code without clearing and updating the dictionary, 
then variables defined in once session will persist to the next.
I'm eager to try your solution.


>> Some code:
>>
>>     object main_module (handle<> (borrowed (PyImport_AddModule
>> ("__main__")))) ;
>>     object dictionary = main_module.attr ("__dict__") ;
>>
>>     // copy the dictionary
>>     PyObject* clean_dict = PyDict_Copy (dictionary.ptr()) ;
>>
>>     // run your python script.
>>
>>     // reset main dictonary
>>     PyDict_Clear (dictionary.ptr()) ;
>>     PuDict_Update (dictionary.ptr(), clean_dict) ;
>>     Py_XDECREF (clean_dict) ;
>
> (nit-picking: all the above could be written using only boost.python)


That it should be :)


>
> Regards,
> Stefan
>
> -- 
>
>      ...ich hab' noch einen Koffer in Berlin...
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