Re: unix time in plot (an Octave problem?)

[Vic Norton]

On Jul 20, 2015, at 4:22 PM, Mike Miller <address@hidden> wrote:

> On Mon, Jul 20, 2015 at 15:39:07 -0400, Vic Norton wrote:
>> I put the unix times above in the following Octave script:
>> printf("This looks right. It's what I want.\n");
>> printf("  %s\n", strftime("%Y-%m-%d %X %Z", gmtime(1420027200)));
>> printf("  %s\n", strftime("%Y-%m-%d %X %Z", gmtime(1435665600)));
>> printf("  %s\n", strftime("%Y-%m-%d %X %Z", gmtime(1451563200)));
>> printf("But shouldn't all the %%z time zones read +0000?\n");
>> printf("  %s\n", strftime("%Y-%m-%d %X %z", gmtime(1420027200)));
>> printf("  %s\n", strftime("%Y-%m-%d %X %z", gmtime(1435665600)));
>> printf("  %s\n", strftime("%Y-%m-%d %X %z", gmtime(1451563200)));
>> The results are a bit disturbing:
>> This looks right. It's what I want.
>>   2014-12-31 12:00:00 UTC
>>   2015-06-30 12:00:00 UTC
>>   2015-12-31 12:00:00 UTC
>> But shouldn't all the %z time zones read +0000?
>>   2014-12-31 12:00:00 -48038628
>>   2015-06-30 12:00:00 -48040837
>>   2015-12-31 12:00:00 -48053659
>> See, for example,
>> http://search.cpan.org/~dexter/POSIX-strftime-GNU-0.0301/lib/POSIX/strftime/GNU.pm
> 
> I agree, I get the same output.
> 
> Two things:
> 
> 1. Note that "%z" is not documented in "help strftime", although I
> agree it is reasonable to expect it to work if you're familiar with the
> standard C function of the same name.
> 
> 2. We use the gnulib implementation of strftime, which I think is where
> the bug lies. If you're willing, you could work up a minimal example to
> verify that the bug lies in gnulib, report it to the gnulib project,
> and we can absorb the fix in Octave.
> 
> If not, at least report a bug on the Octave bug tracker.
> 
> Thanks for the demonstration,
> 
> -- 
> mike

Thanks for the advice, Mike. I don't know anything about gnulib, but I
did report the bug at <https://savannah.gnu.org/bugs>, if that's what
you mean by the Octave bug tracker. Apparently the %z is nonstandard.
In Perl you need the POSIX-strftime-GNU-0.0301 package.

--
Vic