2010/4/20 Ozkan Sezer <[email protected]>:
> On Tue, Apr 20, 2010 at 12:41 PM, Ozkan Sezer <[email protected]> wrote:
>> On Tue, Apr 20, 2010 at 7:37 AM, Kai Tietz <[email protected]> wrote:
>>> Hi Patrick,
>>>
>>> 2010/4/20 Patrick Galbraith <[email protected]>:
>>>> Hi all,
>>>>
>>>> I've stumbled across an issue with gettimeofday() returning an incorrect
>>>> value with mingw-w64. A simple code sample:
>>>>
>>>> #include <stdio.h>
>>>> #include <sys/time.h>
>>>>
>>>> int main (void)
>>>> {
>>>> struct timeval timer;
>>>> int retval;
>>>> retval= gettimeofday(&timer,NULL);
>>>> fprintf(stderr, "retval: %d\n", retval);
>>>> fprintf(stderr, "now: %ld\n", time(0));
>>>> fprintf(stderr, "now: %ld\n", timer.tv_sec);
>>>> return(0);
>>>>
>>>> }
>>>>
>>>> When compiled using -
>>>>
>>>> regular mingw (correct output)
>>>>
>>>> Patrick galbra...@win-7a3e68a2d98 ~/dev/stuff
>>>> $ gcc -o mtime mtime.c
>>>>
>>>> Patrick galbra...@win-7a3e68a2d98 ~/dev/stuff
>>>> $ ./mtime.exe
>>>> retval: 0
>>>> now: 1271722468
>>>> now: 1271722468
>>>>
>>>> mingw-w64:
>>>>
>>>>
>>>> Patrick galbra...@win-7a3e68a2d98 ~/dev/stuff
>>>> $ /c/mingw/bin/x86_64-w64-mingw32-gcc -o mtime mtime.c
>>>>
>>>> Patrick galbra...@win-7a3e68a2d98 ~/dev/stuff
>>>> $ ./mtime.exe
>>>> retval: 0
>>>> now: 1271722480
>>>> now: 31293027
>>>>
>>>> Are there any known issues with gettimeofday() with mingw-w64?
>>>>
>>>> Thanks!
>>>>
>>>> Patrick
>>>
>>> what you are seeing here is that time_t type has changed for x64. x64
>>> doesn't use any longer a 32-bit time_t type. I use 64-bit wide scalar
>>> instead.
>>> If you want to have 32-bit time_t the use please the <timefunction>32
>>> function set and use instead tim32_t type.
>>>
>>> Regards,
>>> Kai
>>
>> I can't see the use of a time_t type anywhere in the report?
>> Is there a misunderstanding somewhere?
>>
>> The problem may be due to strict aliasing violations.
>> A warning doesn't appear with default CFLAGS, but
>> after adding -Wstrict-aliasing=2, you get
>>
>> gettimeofday.c: In function 'getntptimeofday':
>> gettimeofday.c:42: warning: dereferencing type-punned pointer will
>> break strict-aliasing rules
>>
>> The mingw.org version of gettimeofday.c doesn't exhibit
>> such an issue. Proper use of a union as it the mingw.org
>> version might be a solution.
>>
>> --
>> Ozkan
>>
>
> Hmm, changing the FILETIME_1970 macro from 11644473600ull
> to 116444736000000000ULL in gettimeofday.c as in the mingw.org
> version seems to make the testcase output the same value.
>
> Kai, is this correct? (see attached g3.diff.) Please verify.
>
> --
> Ozkan
>
yeah, it is ok for apply and looks right.
Thanks,
Kai
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