Re: [PATCH v2] strbuf: let strbuf_addftime handle %z and %Z itself

From: Ulrich Mueller <ulm@gentoo.org>
Date: Jun 15, 2017, 11:27 UTC
Message-ID: <22850.28477.715057.441985@a1i15.kph.uni-mainz.de>
In-Reply-To: <d578d104-79c6-6c07-db4d-3e4ccb0c0dd9@web.de>

>>>>> On Thu, 15 Jun 2017, René Scharfe wrote:

> Callers can opt out for %Z by passing NULL as timezone name.  %z is
> always handled internally -- this helps on Windows, where strftime would
> expand it to a timezone name (same as %Z), in violation of POSIX.
> Modifiers are not handled, e.g. %Ez is still passed to strftime.

POSIX would also allow other things, like a field width: http://pubs.opengroup.org/onlinepubs/9699919799/functions/strftime.html

$ date '+%8z' +0000200

(But I believe that's not very useful, and supporting it might require duplicating much of strftime's code.)

> Changes from v1:
> - Always handle %z internally.

Minor nitpick: Shouldn't the comment in strbuf.h be updated to reflect that change?

> + * Add the time specified by `tm`, as formatted by `strftime`.  `tz_offset`
> + * and `tz_name` are used to expand %z and %Z internally, unless `tz_name`
> + * is NULL.  `tz_offset` is in decimal hhmm format, e.g. -600 means six
> + * hours west of Greenwich.

Ulrich