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Re: Consensus on MT-, AS- and AC-Safety docs.


On 12/04/2013 06:30 PM, Carlos O'Donell wrote:
On 12/04/2013 05:50 AM, Florian Weimer wrote:
On 12/03/2013 04:27 PM, Carlos O'Donell wrote:

I think that's certainly the right start. File a defect with the
Austin Group tracker and ask them the following things:

* What if any unintended consequences could there be if the
    implementation choose to save and restore errno during
    signal handling?

* Was it ever POSIX's intent to allow a signal handler to
    modify the errno of the interrupted code sequence or was
    that simply a consequence of being a signal handler and
    modifying global state?

... and anything else you think we should get an expert opinion
on before embarking upon a change like this.

Okay, I tried to summarize the previous discussion there:

<http://austingroupbugs.net/view.php?id=807>

Interesting response from Geoff Clare:

"If we make any change as a result of this issue, I think it should
just be to make it explicit that implementations are allowed, but
not required, to restore errno on return from signal handlers."

Which would be a nice addition and clarification to the standard.

How likely is that the Austin Group will ever close this ticket, even with a indeterminate conclusion like "the standard does not specify errno-restoring behavior"? How long should we wait for such a resolution? (I think it's too late for this change for 2.19 anyway.)

--
Florian Weimer / Red Hat Product Security Team


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