Re: [PATCH][BZ #926] Mention timezone for strftime %s

[Rich Felker <dalias at aerifal dot cx>]

On Sat, Oct 12, 2013 at 06:58:35PM +0200, OndÅej BÃlka wrote:
> Hi,
> 
> this is next bug that received no response. Patch is following, take it
> or close bug I am sligthly for adding it.
> 
> 	* manual/time.texi (strftime): Mention that %s uses current
> 	timezone.
> 
> diff --git a/manual/time.texi b/manual/time.texi
> index ff31e28..33a55ef 100644
> --- a/manual/time.texi
> +++ b/manual/time.texi
> @@ -1277,6 +1277,7 @@ but was previously available as a GNU extension.
>  @item %s
>  The number of seconds since the epoch, i.e., since 1970-01-01 00:00:00 UTC.
>  Leap seconds are not counted unless leap second support is available.
> +Note that like mktime, this uses the current time zone instead of tm_gmtoff.
>  
>  This format is a GNU extension.

It should be noted that %s was proposed and seems to have been
accepted for inclusion in the next issue of POSIX, but that this issue
(which offset it uses, or whether it even uses an offset at all) is
not clearly specified. I think there should be an effort to coordinate
this with the Austin Group and either agree on a practice, or agree
that it's implementation-defined, before documenting a particular
behavior.

For what it's worth, I think using the current time zone rather than
tm_gmtoff is bad behavior since it makes %s unusable with struct tm's
obtained from gmtime().

Rich