Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Fri, 14 Aug 2015 10:15:40 -0400
From: Rich Felker <>
Cc: Jan V??el?k <>
Subject: Re: strptime() lacks support for %z

On Fri, Aug 14, 2015 at 11:34:32AM +0200, Szabolcs Nagy wrote:
> * Jan V??el?k <> [2015-08-14 10:00:23 +0200]:
> > On Thursday, August 13, 2015 10:06:50 PM Szabolcs Nagy wrote:
> > > the problem with parsing timezones is that it's not posix
> > > so the desired semantics is not clear (struct tm has no
> > > tz field in posix and it is not obvious how that should
> > > be treated in other apis that use struct tm.. glibc does
> > > something but it should be verified to give consistent
> > > behaviour if we add this to musl and there might be parsing
> > > corner cases when %z is not surrounded by spaces..).
> > 
> > I know it's not specified in POSIX strptime, however it is specified in 
> > strftime. I'm not sure how strictly do you want to stick to POSIX, but it 
> > seems reasonable to me to have the equivalent format support in both 
> > functions, so you can write the time stamp and parse it back.
> > 
> > Anyway, the format in strftime is simple and on fixed width, +hhmm or -hhmm.
> > 
> strftime uses tzset (timezone from TZ) but strptime cannot
> set TZ so it must put the timezone somewhere else.
> so strptime can't be consistent with strftime.
> with tz in struct tm, mktime/localtime no longer roundtrip.

I don't follow. strftime uses the extended fields from struct tm. I
don't see anywhere it depends on tzset, nor reasons why strptime would
need tzset to be called. Am I missing something?


Powered by blists - more mailing lists

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.