[C++-sig] Re: Presenting a Python embedding tutorial

[Charsley, Mark]

> A pseudo-implementation of the constructor and destructor 
> could look like:
> 
>      interpreter()
>      {
>          // Create the main interpreter
>          if (interpreter_count == 0)
>          {
>              Py_Initialize();
>              ...
>          }
>          // Create a sub-interpreter
>          else
>          {
>              ...
>          }
>          interpreter_count++;
>      }
>      ~interpreter()
>      {
>          // Release the main interpreter
>          if (interpreter_count == 1)
>          {
>              Py_Finalize();
>              ...
>          }
>          // Release a sub-interpreter
>          else
>          {
>              ...
>          }
>          interpreter_count--;
>      }


That contains a dangerous flaw - it supposes that PyInitialize hasn't been
called by anyone else, using code other than boost::python. Which means that
code running in a boost::python extension can't create a sub-interpreter
using boost::python. I strongly advise using Py_IsInitialized() instead of a
static count in a C++ class.

Mark


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