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Re: [PATCH 2/3] posix: Improve default posix_spawn implementation
- From: Adhemerval Zanella <adhemerval dot zanella at linaro dot org>
- To: Andreas Schwab <schwab at suse dot de>
- Cc: libc-alpha at sourceware dot org
- Date: Mon, 3 Jul 2017 09:09:55 -0300
- Subject: Re: [PATCH 2/3] posix: Improve default posix_spawn implementation
- Authentication-results: sourceware.org; auth=none
- References: <1494876985-21990-1-git-send-email-adhemerval.zanella@linaro.org> <1494876985-21990-2-git-send-email-adhemerval.zanella@linaro.org> <mvm7ezulvqi.fsf@suse.de> <ed432eaf-2139-6fde-51ba-b85aa06a6ac3@linaro.org> <mvmy3sakegp.fsf@suse.de> <1a5a19ea-7a20-a71c-86ce-e0f302795401@linaro.org> <mvmpodij8ux.fsf@suse.de>
On 03/07/2017 04:08, Andreas Schwab wrote:
> On Jun 29 2017, Adhemerval Zanella <adhemerval.zanella@linaro.org> wrote:
>
>> On 29/06/2017 12:20, Andreas Schwab wrote:
>>> On Jun 29 2017, Adhemerval Zanella <adhemerval.zanella@linaro.org> wrote:
>>>
>>>> Since posix_spawn is not support to set errno in case of failure
>>>
>>> Is it?
>>
>> My understanding of posix_spawn return value [1] states that the error number
>> should be returned as the function return value, not on errno.
>
> But that doesn't forbid spurious writes to errno, does it?
My understanding is POSIX is not strictly regarding spurious errno writes,
but on general information [1] it has the rationale:
"In order to avoid this problem altogether for new functions, these
functions avoid using errno and, instead, return the error number directly
as the function return value; a return value of zero indicates that no
error was detected."
Also, making 'clone' not setting errno should also a QoI IMHO: this is an
Linux extension and making is avoid touching memory that might incur in
some issue should be less prone to errors.
[1] http://pubs.opengroup.org/onlinepubs/9699919799/xrat/V4_xsh_chap02.html