Garbage Collection Question

[Chaman Singh Verma]

Hello,

I am trying to integrate C++ with Python. I read that Python does automatic
garbage collection. I am creating new objects in C++ and passing to Python,
I don't know now who should control deleting the objects. If I create objects
in C++ do I have to clean them or Python will use GC to remove unwanted objects.

Bye.
csv

[Aahz]

Re: Garbage Collection Question

In article <2ce55ce2.03082 81518.4be94efc@ posting.google. com>,
Chaman Singh Verma <csv610@yahoo.c om> wrote:[color=blue]
>
>I am trying to integrate C++ with Python. I read that Python does
>automatic garbage collection. I am creating new objects in C++ and
>passing to Python, I don't know now who should control deleting the
>objects. If I create objects in C++ do I have to clean them or Python
>will use GC to remove unwanted objects.[/color]

Depends whether it's a Python object created with a Python API call. If
not, your objects will never be touched by Python.
--
Aahz (aahz@pythoncra ft.com) <*> http://www.pythoncraft.com/

This is Python. We don't care much about theory, except where it intersects
with useful practice. --Aahz

[Michael Hudson]

Re: Garbage Collection Question

csv610@yahoo.co m (Chaman Singh Verma) writes:
[color=blue]
> I am trying to integrate C++ with Python. I read that Python does
> automatic garbage collection. I am creating new objects in C++ and
> passing to Python, I don't know now who should control deleting the
> objects.[/color]

Um, I think I need more detail to fully answer this.
[color=blue]
> If I create objects in C++ do I have to clean them or Python will
> use GC to remove unwanted objects.[/color]

As Aahz noted, Python only GCs objects it knows about, i.e. PyObjects.

A common pattern is to have a custom Python object encapsulate one of
your C++ objects. So you do something like this:

static PyTypeObject Thing_Type;

struct ThingObject {
PyObject_HEAD
Thing* thing;
}

PyObject* Thing_New()
{
Thing* thing = PyObject_New(Th ingObject, &Thing_Type) ;
thing->thing = new Thing();
return (PyObject*)thin g;
}

void thing_dealloc(P yObject* thing)
{
delete ((ThingObject*) thing)->thing;
thing->ob_type->tp_free();
}

and make sure thing_dealloc ends up in the tp_dealloc slot of
Thing_Type.

HTH,
mwh

--
if-you-need-your-own-xxx.py-you-know-where-to-shove-it<wink>-ly
y'rs - tim
-- Tim Peters dishes out versioning advice on python-dev