[PATCH 2/3] posix: Improve default posix_spawn implementation

[Adhemerval Zanella]

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