DST

[Joel Sherrill]

Eric Norum wrote:
> On Mar 13, 2007, at 6:29 AM, Joel Sherrill wrote:
>
>> Eric Norum wrote:
>>> Does the newlib that's part of RTEMS-4.7 handle the TZ environment  
>>> variable properly?  I've got:
>>>
>>> TZ="CST6CDT,M3.2.0,M11.1.0"
>>>
>>> but RTEMS is still reporting CST time.
>>>
>>>
>>> I built newlib from:
>>> NEWLIB=newlib-1.14.0
>>> NEWLIBDIFF=newlib-1.14.0-rtems4.7-20061019.diff
>>>
>>>
>> What time function are you calling?
>>
>> Internally RTEMS does not know timezone.
>
> Right, which is why I was asking about newlib.  Here's a little test 
> code I stuck into an existing application:
> {
> struct tm *tm;
> time_t now;
> printf("TZ:\"%s\"\n", getenv("TZ"));
> time(&now);
> tm = localtime(&now);
> printf ("%4.4d-%2.2d-%2.2d %2.2d:%2.2d:%2.2d\n", 1900+tm->tm_year, 
> tm->tm_mon, tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec);
> tm = gmtime(&now);
> printf ("%4.4d-%2.2d-%2.2d %2.2d:%2.2d:%2.2d\n", 1900+tm->tm_year, 
> tm->tm_mon, tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec);
> }
>
>
> And here's the output:
> TZ:"CST6CDT,M3.2.0,M11.1.0"
> 2007-02-13 08:04:01
> 2007-02-13 14:04:01
>
> The TZ variable looks right to me.
> The GMT values are correct.  But the local time is 6 hours behind 
> (CST) instead of 5 hours behind (CDT).
>
time() directly calls __gettimeofday_r() which is in cpukit/libcsupport 
and has a comment
that newlib does not have timezone support.   time() passes a NULL to 
__gettimeofday_r()
so even if we did support timezone info at that level, newlib wouldn't 
get it.

Neither the newlib docs nor Linux man page mention timezone at all for 
time().

Should you be calling localtime instead of time?
--joel
> --Eric Norum <norume at aps.anl.gov>
> Advanced Photon Source
> Argonne National Laboratory
> (630) 252-4793
>
>