svn commit: r304928 - in head/lib/libc: amd64/sys i386/sys sys

[Andrey Chernov]

On 28.08.2016 5:33, Andrey Chernov wrote:
> "conforming implementation may have extensions (including additional
> library functions), provided they do not alter the behavior of any
> strictly conforming program.3)"
> 
> ptrace() is extension (additional library function) so can't set errno
> to 0 (it breaks strictly conforming program).

Sorry for misguiding in this particular part. I confuse the "strictly
conforming program" with the "conforming program" term used there too.
"Strictly conforming program" can't call ptrace().

In any case our own ptrace(2) manpage suggest to set errno to 0 manually
_before_ ptrace() call and do not relay on ptrace() to do it by itself:

"Some requests can cause ptrace() to return -1 as a non-error value; to
disambiguate, errno can be set to 0 before the call and checked afterwards."

It will be better to stay common policy about errno even for extensions
to not keep exclusions in the mind.