[BlueOnyx:12828] Re: PHP Date_Diff

[Richard Sidlin]

> -----Original Message-----
> From: blueonyx-bounces at mail.blueonyx.it [mailto:blueonyx-
> bounces at mail.blueonyx.it] On Behalf Of Michael Stauber
> Sent: 12 April 2013 21:35
> To: BlueOnyx General Mailing List
> Subject: [BlueOnyx:12825] Re: PHP Date_Diff
> 
> Hi Richard,
> 
> > Now the developer of the software has looked at the problem we have,
> > and that is, that if some of the entrants are close to another age
> > category, it sometimes puts them in the wrong category as he tells me
> > the data_diff function seems to be calculating things incorrectly. On
> > previous versions of BO and PHP I guess before the function was built
> > in, we had no problems as he used code within his software to do the
> > calculation.
> 
> Fire the developer. ;-)
> 
> Those who program in PHP have learned to avoid the date_diff() function as
> it has issues. It's one of the stupid and lazy "solutions" that came
aboard with
> PHP-5.3.0. Lazy solutions (often bugged!) that offer "simpler" approaches
> than the trusted methods that PHP coders have used successfully in the
past
> decade. I guess that's what you get when you let the point and click crowd
of
> web designers loose at something that was supposed to be an attempt at a
> programming language. ;-)
> 
> Now over various PHP versions this bugged date_diff() - and it's parent
> DateTime() - produce entirely different results. It also depends on the
> timezone you have configured in the php.ini. When the shift over to
daylight
> saving happens, you get weird results when you cross compute dates.
> 
> Even without that: If your script relies on date_diff() it's not really
portable,
> as you will get odd results depending on system settings and used PHP
> versions. So any PHP coder is well advised to not rely on that function,
unless
> the oddities are acceptable or are compensated otherwise.
> 
> You could try another PHP version from http://shop.blueonyx.it like
> 5.3.23 or 5.4.13 and see what kind or results you get there.
> 
> But ideally it would be better if your code would use more reliable and
more
> robust methods for such calculations.
> 
> Now there are many ways to do that. Personally I'd probably do what I have
> been doing the last ten years: Use strtotime() to convert two dates to
unix
> time and then calculate the number of seconds between them.
> Which will produce pretty robust and consistent results, regardless of if
you
> run on Linux, Windows or whatever the PHP version might be.
> 
> And it's not necessarily much more complicated, because it can be as
simple
> as this to avoid usage of date_diff():
> 
> <?php
> $today = strtotime("2013-04-12 15:25:00"); $myBirthDate = strtotime("1971-
> 05-24 09:48:00"); printf("I'm %d days old.", round(abs($today-
> $myBirthDate)/60/60/24));
> ?>
> 
> See:
> 
> http://stackoverflow.com/questions/13711955/php-date-diff-craziness
> http://stackoverflow.com/questions/676824/how-to-calculate-the-
> difference-between-two-dates-using-php
> http://php.net/manual/en/dateinterval.format.php
> http://www.php.net/manual/en/function.date-diff.php
> 
> 
> --
> With best regards
> 
> Michael Stauber

Thanks Michael. So I believe that the developer includes the function in his
code so the diff_date is not required in PHP. Is it possible to turn that
function off somehow?

Apologies if I haven't understood totally.

Richard