[Python-Dev] EINTR handling...

[Gregory P. Smith]

On Fri, Aug 30, 2013 at 10:57 AM, Guido van Rossum <guido at python.org> wrote:

> I don't have a strong opinion on this either. The distinction between
> send() and send_all() makes sense to me though (send_all() works hard to
> get all your data out, send() only does what it can quickly).
>
> Personally for calls like select() I think returning early on EINTR makes
> sense, it's usually part of a select loop anyway.
>
> The only thing I care deeply about is that you shouldn't restart anything
> before letting a Python-level signal handler run. A program might well have
> a Python signal handler that must run before the I/O is restarted, and the
> signal handler might raise an exception (like the default SIGINT handler,
> which raises KeyboardInterrupt).
>

I see http://bugs.python.org/issue18885 has been filed to track this
discussion so we should probably move it there (I've added comments).

TL;DR you can't simply retry a system call with the exact same arguments
when you receive an EINTR. There are some system calls for which that will
not do what the programmer intended.


>
>
> On Fri, Aug 30, 2013 at 10:02 AM, Antoine Pitrou <solipsis at pitrou.net>wrote:
>
>> On Fri, 30 Aug 2013 12:29:12 +0200
>> Charles-François Natali <cf.natali at gmail.com> wrote:
>> >
>> > Furthermore, the stdlib code base is not consistent: some code paths
>> > handle EINTR, e.g. subprocess, multiprocessing, sock_sendall() does
>> > but not sock_send()...
>> > Just grep for EINTR and InterruptedError and you'll be amazed.
>> >
>> > GHC, the JVM and probably other platforms handle EINTR, maybe it's
>> > time for us too?
>>
>> I don't have any precise opinion on this. It's true that we should have
>> a systematic approach, I just don't know if all interfaces should
>> handler EINTR automatically, or only the high-level ones.
>> (for the sake of clarity, I'm fine with either :-))
>>
>> Regards
>>
>> Antoine.
>>
>>
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>
>
>
> --
> --Guido van Rossum (python.org/~guido)
>
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