note 106665 deleted from function.define by danbrown
| From: | danbrown@php.net | Date: | Tue, 29 Nov 2011 15:44:21 +0000 |
| Subject: | note 106665 deleted from function.define by danbrown | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-184791@lists.php.net to get a copy of this message | ||
Note Submitter: Frogger
----
remark to webmaster@PersonalInformationTechnology's note:
The better way is to use all the nice functions php provides, such as defined(), array_key_exists(),
property_exists() and so on.
A variable test like if ($var) will fail in many ways (in reference to what the developer expected).
In this specific case it seems to be obvious to write
<?php
if(defined('CONST_DEFINED') && CONST_DEFINED)
{/* use them */}
?>
But this will only let you know, CONST_DEFINED has been defined and has any (positive) value - which
could also be a string, a number or something other.
<?php
if(defined('CONST_DEFINED') && CONST_DEFINED === true)
{/* use them */}
?>
should be the option used.
This guarantees CONST_DEFINED is a defined constant AND that it has a boolean type due to the
implicit type compare of the ===
I.e.: Similar results will give
if( array_key_exists('myKey', $myArray))
instead of
if (isset($myArray['myKey',])) which could return unexpected results.
In case of include necessary files use require() to ensure they have been included or include the
lines
if (!defined('MY_CONST'))
define('MY_CONST', 'any default value or a value which results in a caught
error');