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Re: strptime doesn't fill in tm_wday and tm_yday.
On May 12 11:01, Peter Rosin wrote:
> Den 2011-05-11 19:34 skrev Corinna Vinschen:
> > On May 11 16:52, Peter Rosin wrote:
> >> Hello!
> >> The following STC hints at a problem in strptime:
> >> Opengroup has this to say about only filling in some fields:
> >> "It is unspecified whether multiple calls to strptime()
> >> using the same tm structure will update the current
> >> contents of the structure or overwrite all contents of
> >> the structure. Conforming applications should make a
> >> single call to strptime() with a format and all data
> >> needed to completely specify the date and time being
> >> converted."
> >> but I don't think it applies since indeed I do completely specify
> >> the date in my strptime call.
> > The Cygwin implementation of strptime is taken from NetBSD and enhanced
> > only in terms of support for the E and O modifiers. The NetBSD and
> > OpenBSD versions also support a non-POSIX format specifier %u (day of
> > week, monday = 1). Other than that, the Cygwin strptime behaves exactly
> > as the BSD implementation. tm_wday is only set if you specify %a, %A or
> > %w. tm_yday is only set if you specify %j.
> > Despite the example in the strptime man page of POSIX.1-2008, POSIX does
> > not specify that strptime has to fill out tm fields which are not also
> > specified in the format string. You should better memset the tm
> > structure to 0 before calling strptime.
> Since you pulled out your "POSIX does not require it" card, I'm grasping
> for my "Cygwin should behave like Linux" card. :-)
I'm not so much pulling the POSIX card, but rather the BSD/upstream
card. Consider this: The Cygwin version behaves pretty exactly like
the BSD version since it *is* the BSD version. Should you ever have
to port your application to Open/Free/NetBSD, you will see the exact
same problem. Whatever we do with the Cygwin strptime eventually,
you still have to consider that your application is *not* portable.
> Seriously, of course I need to handle quirks in strptime if I want the
> users of my application to be happy, but that does not mean that strptime
> can't be a little bit more helpful on Cygwin. Maybe someone with a
> copyright assignment can find some inspiration in the patch  I sent
> for the newlib strptime?
I'll take a look.
Corinna Vinschen Please, send mails regarding Cygwin to
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