[Mesa-dev] [PATCH 03/25] threads: update for late C11 changes

[Nicolai Hähnle]

On 23.10.2017 13:15, Emil Velikov wrote:
> Hi Nicolai,
> 
> On 22 October 2017 at 20:07, Nicolai Hähnle <nhaehnle at gmail.com> wrote:
>> From: Nicolai Hähnle <nicolai.haehnle at amd.com>
>>
>> C11 threads were changed to use struct timespec instead of xtime, and
>> thrd_sleep got a second argument.
>>
> As xtime was replaced with timespec there's a couple of odd bits in the code.
> 
> 
>> See http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1554.htm and
>> http://en.cppreference.com/w/c/thread/{thrd_sleep,cnd_timedwait,mtx_timedlock}
>>
>> Note that cnd_timedwait is spec'd to be relative to TIME_UTC / CLOCK_REALTIME.
>>
>> Cc: Jose Fonseca <jfonseca at vmware.com>
>> ---
>>   include/c11/threads.h           | 11 -----------
>>   include/c11/threads_posix.h     | 39 +++++++++++++++------------------------
>>   include/c11/threads_win32.h     | 37 +++++++++++++++++++------------------
>>   src/egl/drivers/dri2/egl_dri2.c | 24 +++++++++++++-----------
>>   4 files changed, 47 insertions(+), 64 deletions(-)
>>
>> diff --git a/include/c11/threads.h b/include/c11/threads.h
>> index 573348d8091..3c3f23a8ab8 100644
>> --- a/include/c11/threads.h
>> +++ b/include/c11/threads.h
>> @@ -23,42 +23,31 @@
>>    * FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
>>    * SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
>>    * FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
>>    * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
>>    * DEALINGS IN THE SOFTWARE.
>>    */
>>   #ifndef EMULATED_THREADS_H_INCLUDED_
>>   #define EMULATED_THREADS_H_INCLUDED_
>>
>>   #include <time.h>
>> -#ifdef _MSC_VER
>> -#include <thr/xtimec.h>  // for xtime
>> -#endif
>>
>>   #ifndef TIME_UTC
>>   #define TIME_UTC 1
>>   #endif
>>
>>   #include "c99_compat.h" /* for `inline` */
>>
>>   /*---------------------------- types ----------------------------*/
>>   typedef void (*tss_dtor_t)(void*);
>>   typedef int (*thrd_start_t)(void*);
>>
>> -#ifndef _MSC_VER
>> -struct xtime {
>> -    time_t sec;
>> -    long nsec;
>> -};
>> -typedef struct xtime xtime;
>> -#endif
>> -
> 
> We don't have a fall-back declaration of the struct, yet we use it
> below and provide a timespec_get() implementation.
> I'd imagine you haven't tested this on Windows (hence Jose in CC)?

Right on both counts, as I don't really have a way of testing on Windows.


> Quick search suggests that MSVC 2015 was the first one that introduces
> the struct and timespec_get.
> 
> If we're safe as-is, please add a comment with some details - I'd
> imagine Jose had better knowledge in the area.
> 
> 
>>   /*-------------------- 7.25.7 Time functions --------------------*/
>>   // 7.25.6.1
>> +#if 0
> I'd just drop the hunk mentioning that timespec_get() is part of time.h

I wasn't sure when timespec_get was introduced, so I thought it safer to 
keep it around for a while in case we run into systems where time.h 
doesn't provide it.

I can add a comment, or remove it entirely if you think that's not a 
concern.

Cheers,
Nicolai

> 
> 
> Thank
> Emil
> 


-- 
Lerne, wie die Welt wirklich ist,
Aber vergiss niemals, wie sie sein sollte.