I'd like to suggest some improvements from mmap

1) mmap assign to slice only accepts a string.  This is unfortunate,
because AFAIK a string can only be created by copying data, and this is
wasteful for large data transfers.  mmap should accept any object
supporting buffer protocol as well as string.

2) buffer (mmap_obj) gives a read_only buffer.  There should be a way to
make this read_write.  I suggest 'as_buffer' member.

3) mmap_obj does not support weak ref.  This is needed for proper
lifetime management using boost::python

As for 2), the buffer() function is deprecated and is replaced in 3.0 by
new object called memoryview() (together with a revamped internal API
for taking and releasing buffers).

1) and 2) have been fixed in Python 3.x. mmap supports writable memory views and slice assignment from any object that supports the buffer protocol.

3) is still an issue as mmap objects are not weakref-able yet. It should be easy to add __weakref__ to mmap objects.

It's a trivial task for any Python developer with some C experience.

I've uploaded a patch to make mmap_obj support weakref. A test is included in the patch.

Thanks Valerie. I've tested your patch and it looks good to me.
Have you signed and sent a contributor's agreement?
http://www.python.org/psf/contrib/

I just signed and sent the agreement electronically. Let me know if there is anything else I need to do.

New changeset 1754b7900da1 by Antoine Pitrou in branch 'default':
Issue #4885: Add weakref support to mmap objects.  Patch by Valerie Lambert.
http://hg.python.org/cpython/rev/1754b7900da1

Your patch is now committed. Thanks for contributing!