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devel / comp.lang.python / Re: Calling pselect/ppoll/epoll_pwait

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o Re: Calling pselect/ppoll/epoll_pwaitBarry

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Re: Calling pselect/ppoll/epoll_pwait

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From: barry@barrys-emacs.org (Barry)
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Subject: Re: Calling pselect/ppoll/epoll_pwait
Date: Sun, 4 Dec 2022 09:55:24 +0000
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 by: Barry - Sun, 4 Dec 2022 09:55 UTC

On 3 Dec 2022, at 13:13, Weatherby,Gerard <gweatherby@uchc.edu> wrote:



Signalfd and select could probably be made to work if one codes around
the race conditions pselect is provided to avoid. I’m not sure if using
the GIL (for CPython) is sufficient or if a dedicated concurrency
control (e.g. lock, mutex, semaphore) is necessary.

An alternative is to call the C library function via a wrapper. I had
need to use setfsuid on a project a couple of years ago and found this
example:

[1]https://gist.github.com/atdt/ebafa299e843a767139b

 

I read this on SO when researching your question.
Search for epoll and signal.

(I would post the link but ipad turns the link into an image…)

I assume that the lack of pepoll means you can use epoll and

signalfd without race conditions. The trick seems to be setting

the signal to ignore.

Barry

 

From: Python-list <python-list-bounces+gweatherby=uchc.edu@python.org>
on behalf of Barry <barry@barrys-emacs.org>

Date: Friday, December 2, 2022 at 7:02 PM
To: Ian Pilcher <arequipeno@gmail.com>
Cc: python-list@python.org <python-list@python.org>
Subject: Re: Calling pselect/ppoll/epoll_pwait

*** Attention: This is an external email. Use caution responding,
opening attachments or clicking on links. ***

> On 2 Dec 2022, at 20:03, Ian Pilcher <arequipeno@gmail.com> wrote:
>
> Does Python provide any way to call the "p" variants of the I/O
> multiplexing functions?
>
> Looking at the documentation of the select[1] and selectors[2]
modules,
> it appears that they expose only the "non-p" variants.
>
> [1]
[2]https://urldefense.com/v3/__https://docs.python.org/3/library/select.html__;!!Cn_UX_p3!hClFFo4XdiwQAhHxDbHA5zFr490Of9uheHSf84V9cREMHyw1kX-baG5HzXWMt-hFLP30q6DpSUb2G_OD5qBjeA$
> [2]
[3]https://urldefense.com/v3/__https://docs.python.org/3/library/selectors.html__;!!Cn_UX_p3!hClFFo4XdiwQAhHxDbHA5zFr490Of9uheHSf84V9cREMHyw1kX-baG5HzXWMt-hFLP30q6DpSUb2G_MwNjgO8A$

Can you use signalfd and select/poll/epoll?

Barry

>
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References

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1. https://gist.github.com/atdt/ebafa299e843a767139b
2. https://urldefense.com/v3/__https:/docs.python.org/3/library/select.html__;!!Cn_UX_p3!hClFFo4XdiwQAhHxDbHA5zFr490Of9uheHSf84V9cREMHyw1kX-baG5HzXWMt-hFLP30q6DpSUb2G_OD5qBjeA$
3. https://urldefense.com/v3/__https:/docs.python.org/3/library/selectors.html__;!!Cn_UX_p3!hClFFo4XdiwQAhHxDbHA5zFr490Of9uheHSf84V9cREMHyw1kX-baG5HzXWMt-hFLP30q6DpSUb2G_MwNjgO8A$
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devel / comp.lang.python / Re: Calling pselect/ppoll/epoll_pwait

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