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From: Barry <barry@barrys-emacs.org>
Newsgroups: comp.lang.python
Subject: Re: Best (simplest) way to share data between processes
Date: Sun, 7 Jul 2024 23:27:01 +0100
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> On 7 Jul 2024, at 22:13, Chris Green via Python-list <python-list@python.o=
rg> wrote:
>=20
> a simple file lock can then
> be used to prevent simultaneous access (well, simultaneous access when
> the writing process is writing).

There is a simple pattern to make this robust.

Write new values to a tmp file.
Close the tmp file.
Then use os.rename(tmpfile, productionfile).

This is guaranteed that any process that reads the file will only see all th=
e old file contents or all the new file contents,  never a mix of both.

Barry