Problems embedding python 2.6 in C++
gagsl-py2 at yahoo.com.ar
Mon Feb 1 23:59:32 CET 2010
En Mon, 01 Feb 2010 18:21:56 -0300, Paul <gobladoome at gmail.com> escribió:
> I'm extending some old Visual Studio 6 code to add embedded python
> scripting. It works fine most of the time but some python function calls
> not work as expected.
> The C++ code is a multithreaded MFC application. I was assuming that it
> GIL issues but I have tried using the manual locking (PyEval_SaveThread &
> PyEval_RestoreThread) and what seems to be the current method
> (PyGILState_Ensure & PyGILState_Release)
> Here's the error I'm getting:
> Traceback (most recent call last):
> File "...scripts\receipt_parser.py", line 296, in
> details = extract_transaction_details_section(test)
> File "...scripts\receipt_parser.py", line 204, in
> for line in base_details:
> TypeError: expected string or Unicode object, NoneType found
> base_details is a list of strings (I can just define it like
> 'base_details=["1","2","3"...]' on the line previous) and the code runs
> when run from standard interpreter. Many other function calls work fine
> the embedded app.
> I create and then Py_DECREF the function parameters and the return value
> after each function call. The module import is created at C++ object
> constructor and then Py_DECREF'd in the desctuctor
Usually, errors in reference count handling prevent objects from being
destroyed (a memory leak) or generate a GPF when accessing an
now-inexistent object. In principle I'd look elsewhere.
> Anyone else had issues of this kind?
Hard to tell without more info. base_details is built in C++ code? Is it
actually a list, or a subclass defined by you?
A common error is to forget to check *every* API function call for errors,
so errors get unnoticed for a while but are reported on the next check,
which may happen in an entirely unrelated function.
> My next try will be to use
> sub-interpreters per thread.
I would not do that - I'd try to *simplify* the code to test, not make it
Does it work in a single-threaded application?
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