newbie question

Sean Blakey pythonista at gmail.com
Tue Mar 29 01:20:41 CEST 2005


On 28 Mar 2005 15:00:37 -0800, shama.bell at gmail.com
<shama.bell at gmail.com> wrote:
> Hello,
> 
> How do i create two memory mapped buffers(mmap) and pass an index to
> select which one needs to be populated?
> 
> Is it possible to define the size of the buffer?
> 
> -SB
> 
> --
> http://mail.python.org/mailman/listinfo/python-list
> 

http://docs.python.org/lib/module-mmap.html

I haven't tried it, but it should be pretty straightforward to create
two mmaped buffers.

Step 1: Import the mmap module.

Step 2: Create or find the file you want to map. Open it, and get the
fileno. Call mmap.mmap, passing the fileno and buffer size.

Repeat Step 2 with a different file to create a second mmaped buffer.

I'm not sure what you mean by "and pass an index to select which one
needs to be populated". If you pack the buffers into a
tuple/list/other sequence object, it should be easy to access them by
index:

>>> buffers = (buffer_1, buffer_2)
>>> do_something_to(buffers[0])
>>> do_something_else_with(buffers[1])

To mmap buffers, you MUST define the size.

I'm sorry I can't be more helpful; perhaps if you gave a higher-level
description of what you are trying to accomplish, I could give better
pointers in the right direction.

-- 
Sean Blakey
Saint of Mild Amusement, Evil Genius, Big Geek
Python/Java/C++/C(Unix/Windows/Palm/Web) developer
quine = ['print "quine =",quine,"; exec(quine[0])"'] ; exec(quine[0])



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