[PATCH] misc/tst-clone3: Fix waiting for exited thread.

[Stefan Liebler]

On 02/12/2019 01:53 PM, Stefan Liebler wrote:
> On 02/11/2019 01:11 PM, Adhemerval Zanella wrote:
>>
>>
>> On 11/02/2019 08:59, Florian Weimer wrote:
>>> * Stefan Liebler:
>>>
>>>> I've first tried to include atomic.h, but it failed building on
>>>> x86_64. Thus I'm using the c11 atomic load in the updated patch.
>>>> Okay to commit?
>>>>
>>>>
>>>> As information, I've observed those gcc errors on x86_64:
>>>> In file included from ../sysdeps/unix/sysv/linux/x86_64/sysdep.h:30,
>>>> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â  from ../sysdeps/x86_64/nptl/tls.h:28,
>>>> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â  from ../sysdeps/x86/atomic-machine.h:23,
>>>> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â  from ../include/atomic.h:50,
>>>> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â  from ../sysdeps/unix/sysv/linux/tst-clone3.c:29:
>>>> ../sysdeps/unix/sysv/linux/dl-sysdep.h: In function
>>>> ‘_dl_discover_osversion’:
>>>> ../sysdeps/unix/sysv/linux/dl-sysdep.h:31:42: error: expected
>>>> declaration specifiers before ‘attribute_hidden’
>>>> Â  extern int _dl_discover_osversion (void) attribute_hidden;
>>>> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â  ^~~~~~~~~~~~~~~~
>>>
>>> That's because the test isn't in tests-internal.
>>>
>>>> +Â Â Â  while ((__tid = __atomic_load_n (ctid_ptr, __ATOMIC_ACQUIRE)) 
>>>> != 0)Â Â Â  \
>>>
>>> Actually, that's not a C11 atomic construct, but I think it's okay to
>>> use that here.  (The C11 stuff lives in <stdatomic.h> and should be
>>> functionally equivalent.)
>>>
>>> Sorry, this is a pet peeve of mine.  We have three different atomic
>>> access facilities that people refer to as C11 atomics: Our own
>>> <atomic.h>, the GCC __atomic builtins, and <stdatomic.h>.
>>>
>>> I still think this contributes to cognitive load, and we should
>>> eliminate all but one (leaving us with new-style atomics and the old
>>> macros in <atomic.h>).  The GCC __atomic builtins have the best freely
>>> available documentation, so they are a natural candidate IMHO.
>>
>> It really annoying that C11 standard is not freely available from ISO,
>> although the working draft is still open [1]. I don't have a strong
>> opinion, but since there is support in the language itself and they
>> are fully supported by the compiler I also don't see why not prefer it.
>>
>> [1] http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1570.pdf
>>
> Then I have a further update of the patch which uses stdatomic.h and 
> atomic_load_explicit.


ping
okay to commit?