[Python] C API: module cleanup function

En Fri, 29 Jan 2010 19:50:52 -0300, Mr.M <mrm at unknown.nospam> escribi?:

I can't figure out if there is a way to run a specialized cleanup
function when a module needs to be "unloaded" (i.e. just before a
reload() or when i quit the interpreter).

Gabriel Genellina ha scritto:
I think what you want to do isn't possible with Python 2, and it's one
of the reasons the module handling was redesigned in Python 3.x; see PEP
3121.

Mr.M, 29.01.2010 23:50:
I can't figure out if there is a way to run a specialized cleanup
function when a module needs to be "unloaded" (i.e. just before a
reload() or when i quit the interpreter).

I'm thinking of something like tp_dealloc.

If I call Py_InitModule3 and look at module->ob_type->tp_dealloc, I find
that Python provides a default tp_dealloc for me.

Now, suppose my module needs to allocate some resources at startup, I'm
not sure, but I think I'd have to do it in my PyMODINIT_FUNC, right?

But, if I reload() my module or if I quit the Python interpreter, I'd
like to free those resources (before allocate them again, in case of a
reload).

Is there a way to make this work?

Stefan Behnel ha scritto:
Gabriel already pointed you to the module cleanup support in Py3, which can
be used to provide reload capabilities to your module.

In Py2, there are at least some ways to free resources when terminating the
interpreter. See the "atexit" module and the Py_AtExit() function:

http://docs.python.org/library/atexit.html
http://docs.python.org/c-api/sys.html

Note that both have their specific limitations, though, as you can see from
the docs.

Also note that it might help you to take a look at Cython, a Python-to-C
compiler for writing fast C extensions. It has an option for generating
module-level cleanup code automatically, and generally simplifies writing
binary extension modules quite a bit.

Stefan

Mr.M, 30.01.2010 14:24:
Could I allocate my resources in a "static" object linked to my module?

Stefan Behnel ha scritto:
Note that there is the type() builtin function which returns the type given
an instance. So you can't hide the type.