Re: [Qemu-devel] [PATCH] error: error_setg_errno(): errno may be clobbered

[Sascha Silbe]

Dear Markus,

Markus Armbruster <address@hidden> writes:

> Sascha Silbe <address@hidden> writes:
>
>> As a general policy, we want callers to save errno
>> themselves. error_setg_internal() currently goes out of its way to
>> preserve errno,
>
> In other words, "error_setg_errno(): errno may be clobbered" is a lie :)

No, it's just standardese (though it should be in capital letters for
that) for "do not rely on it, we may change our mind any time". :)


>>                 so with the API documentation not mentioning it either
>> way, callers might come to rely on the current behaviour of the
>> implementation.
>
> According to Max, we rely on the errno-saving behavior in several places
> already, and don't intend to change them.
>
>>                 Spell out that we don't want to make that promise.
>
> Well, we already did, tacitly.  Let's make the promise explicit.  Could
> you post the patch?

Sure [1]. Like a good lawyer, I can argue either way, even within the
same case. ;)

Sascha

[1] mid:address@hidden
    "[PATCH] error: error_setg_errno(): errno gets preserved" by Sascha
    Silbe <address@hidden>, sent on 2016-07-27.
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