Re: [PATCH v2 4/4] c2y: Add function cnd_timedwait_base and mtx_timedlock_base

["罗勇刚(Yonggang Luo)" <luoyonggang@gmail.com>]

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On Thu, Jun 22, 2023 at 3:05 AM enh <enh@google.com> wrote:
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>
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> On Wed, Jun 21, 2023 at 11:39 AM 罗勇刚(Yonggang Luo) <luoyonggang@gmail.com>
wrote:
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>>
>>
>> On Wed, Jun 21, 2023 at 10:31 PM enh <enh@google.com> wrote:
>> >
>> >
>> >
>> > On Wed, Jun 21, 2023 at 2:21 AM 罗勇刚(Yonggang Luo) <
luoyonggang@gmail.com> wrote:
>> >>
>> >>
>> >>
>> >> On Wed, Jun 21, 2023 at 4:41 AM Joseph Myers <joseph@codesourcery.com>
wrote:
>> >> >
>> >> > On Wed, 21 Jun 2023, Yonggang Luo via Libc-alpha wrote:
>> >> >
>> >> > > diff --git a/sysdeps/pthread/threads.h b/sysdeps/pthread/threads.h
>> >> > > index d88d7a3ddd..4f61ad9236 100644
>> >> > > --- a/sysdeps/pthread/threads.h
>> >> > > +++ b/sysdeps/pthread/threads.h
>> >> > > @@ -146,14 +146,22 @@ extern int mtx_lock (mtx_t *__mutex);
>> >> > >  #ifndef __USE_TIME_BITS64
>> >> > >  extern int mtx_timedlock (mtx_t *__restrict __mutex,
>> >> > >                         const struct timespec *__restrict
__time_point);
>> >> > > +extern int mtx_timedlock_base (mtx_t *__restrict __mutex, int
time_base,
>> >> > > +                               const struct timespec *__restrict
__time_point);
>> >> >
>> >> > As noted, this should be conditional on __USE_GNU.  Since you
didn't make
>> >> > it conditional, I'd expect it to have failed the conform/ namespace
tests
>> >> > - both for the mtx_timedlock_base name itself if there weren't
incorrect
>> >> > conform/ changes in the patch series, and for the time_base
parameter
>> >> > (parameters in installed headers should always have a leading __).
How
>> >> > did you test these patches?
>> >>
>> >> I am not testing these patches yet(as a new contributor for glibc,
don't know how to do that yet),
>> >> and for this patch, I'd like to know if the prototype of these two
functions is proper first
>> >>
>> >> int mtx_timedlock_base(mtx_t *restrict m, int time_base, const struct
timespec *restrict ts);
>> >>
>> >> int cnd_timedwait_base(cnd_t *restrict c, mtx_t *restrict m, int
time_base, const struct timespec *restrict ts);
>> >>
>> >> The function name was suggested by Jens Gustedt, and indeed I also
thought about this name in the first place(because posix has cond_clockwait
and mutex_clocklock already). And seems enh also like this
>> >
>> >
>> > well, to the extent that i think "pthreads that's also available on
Windows" is useful to some, sure, i'll continue to add the trivial inline
functions to bionic so that this is actually portable (
https://android.googlesource.com/platform/bionic/+/master/libc/include/bits/threads_inlines.h).
but for Android host tools themselves, i think we'll continue to use
std::thread or pthreads via mingw.
>> >
>> > but my real feedback earlier was the same as what you're seeing here:
"since this is a WG14-driven thing, it should come as a proposal from there
first". anyone using bionic or glibc already has perfectly good pthread
apis, so no real need for this stuff until/unless it's in Windows. (and
last time i looked, Windows hadn't actually implemented the existing
<threads.h> stuff yet?)
>>
>> Yeah, you are correct, windows msvc doesn't have either pthread or c11
threads, and pthreads is so huge, so there is multiple third-party c11
threads implementation for MSVC, that's why I wanna c2y threads comes with
monotonic mtx_timedlock cnd_timedwait support, so that the third-party c11
threads implementation have a consistence API to implement.
>
>
> if MS didn't bother to implement the C11 functions, why do you think
they'd implement any future additions?

I don't bother MS if they will implement the C11 functions, I just want a
set of cross-platform threads api(c11 threads) to use (non-posix
non-pthreads), we can always polyfill that API when the native libc doesn't
support that.
The API is more important than who would implement it

>
>>
>> So my question, anyone in this threads have suggestion about the newly
proposed API:
>>
>>  int mtx_timedlock_base (mtx_t*, int, const struct timespec*);
>>  int cnd_timedwait_base (cnd_t*, mtx_t*, int, const struct timespec*);
>
>
> don't existing functions put the `int __base` last? sounds like a
question for WG14 rather than c library implementors though --- as long as
this isn't supported on the platform that doesn't have pthreads, it's not
filling any obvious need.
>
>>
>> >
>> >>
>> >> If we have minimal agreement about this proposal, I'd like to add
tests for it. But still, I don't think
>> >> __USE_GNU is a good name for it, because it's for C2y or C3x, any
better option for this, so that it's not GNU restricted, for example,
suppose MSVC also wants to implement this?
>> >>
>> >>
>> >> >
>> >> > > +extern int __REDIRECT (mtx_timedlock_base, (mtx_t *__restrict
__mutex,
>> >> > > +                                            int time_base,
>> >> > > +                                            const struct
timespec *__restrict
>> >> > > +                                            __time_point),
>> >> > > +                       __mtx_timedlock_base64);
>> >> >
>> >> > Likewise, should be conditional on __USE_GNU and time_base should be
>> >> > __time_base.
>> >> >
>> >> > > +extern int cnd_timedwait_base (cnd_t *__restrict __cond,
>> >> > > +                               mtx_t *__restrict __mutex, int
time_base,
>> >> > > +                               const struct timespec *__restrict
__time_point);
>> >> >
>> >> > > +extern int __REDIRECT (cnd_timedwait_base, (cnd_t *__restrict
__cond,
>> >> > > +                                            mtx_t *__restrict
__mutex,
>> >> > > +                                            int time_base,
>> >> > > +                                            const struct
timespec *__restrict
>> >> > > +                                            __time_point),
>> >> >
>> >> > Likewise.
>> >> >
>> >> > --
>> >> > Joseph S. Myers
>> >> > joseph@codesourcery.com
>> >>
>> >>
>> >>
>> >> --
>> >>          此致
>> >> 礼
>> >> 罗勇刚
>> >> Yours
>> >>     sincerely,
>> >> Yonggang Luo
>>
>>
>>
>> --
>>          此致
>> 礼
>> 罗勇刚
>> Yours
>>     sincerely,
>> Yonggang Luo



--
         此致
礼
罗勇刚
Yours
    sincerely,
Yonggang Luo