[patch] For BZ #17328, mark __errno_location with __attribute__((returns_nonnull)) for gcc >=4.9.0

[Paul Pluzhnikov]

+cc zackw@panix.com

On Sat, Feb 28, 2015 at 5:17 PM, Rich Felker <dalias@libc.org> wrote:
> On Sat, Feb 28, 2015 at 02:03:11PM -0800, Paul Pluzhnikov wrote:
>> Greetings,
>>
>> Tested on Linux/x86_64 with gcc-4.8 and 5.0.
>
> No objection, but I'm curious if there's any practical benefit of
> this. I can't think of many situations where knowledge that
> &errno!=NULL would assist the compiler in optimizing or diagnostics.

Hmm, maybe you are right.

I was reading https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58689 and
threads linked from it, and it really looks like not much is gained
inside (or outside) GLIBC -- it's not like anyone ever checks whether
__errno_location() returned NULL.

Zack,

Do you have any additional motivation for filing
https://sourceware.org/bugzilla/show_bug.cgi?id=17328

Thanks!
-- 
Paul Pluzhnikov