[tz] Irish Standard Time vs Irish Summer Time

Michael H Deckers michael.h.deckers at googlemail.com
Tue Dec 12 15:16:29 UTC 2017

On 2017-12-10 22:16, Paul Eggert wrote:
>> Michael H Deckers via tz wrote:
>>>        The definition
>>>        of the tm_isdst flag does not even mention standard time
>> True, but other parts of POSIX make it clear that when tm_isdst is zero,
>> standard time is intended. See:
>> http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08_03
>> and look at the TZ environment variable: POSIX says that its first few letters
>> correspond to standard time and that later letters correspond to daylight saving
>> time.

     The meaning of fields in a POSIX TZ string does not define the 
meaning of the
     tm_isdst member of struct tm, which is only a matter of the C 
standard; POSIX
     cannot modify that meaning (they can only add extensions).

     Michael Deckers.

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