[Numpy-discussion] memmap close() and flush()

Fernando Perez fperez.net at gmail.com
Wed Jan 31 11:53:48 CST 2007


On 1/31/07, Travis Oliphant <oliphant at ee.byu.edu> wrote:
> Fernando Perez wrote:

> I don't know.  If you have other things pointing to it, should you
> really close it?

Well, it's like a file: you can close it because you've decided it's
time to close it, and I think it's better that other references get an
exception if they try to write to it when they shouldn't:

In [2]: file1 = open('foo','w')

In [3]: file1.write('Some text')

In [4]: file2 = file1

In [5]: file1.close()

In [6]: file2.write("I'm not the original owner but I'll try to write anyway")
---------------------------------------------------------------------------
exceptions.ValueError                                Traceback (most
recent call last)

/home/fperez/<ipython console>

ValueError: I/O operation on closed file


This seems like the right API to me.

> At any rate you have access to the mmap file through the _mmap
> attribute.  So, you can always do
>
> self._mmap.close()

I don't like an API that encourages access to internal semi-private
members, and it seems to me that closing the object is a reasonably
top-level operation whose impmlementation details (in this case the
existence and name of the _mmap member) should be encapsulated out.

Cheers,

f


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