[Patches] [ python-Patches-477161 ] New "access" keyword for mmap

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Thu, 01 Nov 2001 07:12:04 -0800


Patches item #477161, was opened at 2001-11-01 07:12
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Category: Modules
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Jay T Miller (jaytmiller)
Assigned to: Nobody/Anonymous (nobody)
Summary: New "access" keyword for mmap

Initial Comment:
The attached patch adds a new keyword parameter to mmap
which provides a platform independent way of asking for
3 basic kinds of mmaps:   readonly, write-through, and
copy-on-write.  For now, platform independent means
UNIX and Win32.

A readonly mmap creates a true readonly section of the
process memory map, but python level access is guarded
so that attempts to write the section (or fetch a
writeable buffer) raise a ValueError exception.  A
readonly mmap is not resizeable.

A write-through memory map is both readable and
writeable, and updates to the memory are reflected onto
the underlying file.

A copy-on-write memory map is both readable and
writeable, but updates to the memory are *not*
reflected on the underlying file.  A copy-on-write mmap
is not resizeable.

The patch modifies mmapodule.c,  libmmap.tex, and
test_mmap.py.



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