[BlueOnyx:12831] Re: PHP Date_Diff

[Eric Peabody]

Richard,

You can block functions in php.ini using the disable_functions 
directive.  See 
http://www.php.net/manual/en/ini.core.php#ini.disable-functions.

I'm not sure you really want to do that since this will block the 
function for all sites on the server.

Eric


On 4/12/13 7:03 PM, Richard Sidlin wrote:
>
>> -----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
>
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