Works faster that use __DIR__ instead of dirname(__FILE__) .

[kmvan]

We have better choice to improve performance.

Why not use __DIR__ instead of dirname(__FILE__) to improve performance? (require PHP5.3+)

I think we needn't to be compatible with PHP5.2, PHP5.2 is out-date and unsafe.

Please, it's time to use PHP5.3 or higher new features.

[knutsp]

As long as WordPress requires PHP version 5.2.4 or greater this will have to wait.

[kmvan]

So disappointed :(

[SergeyBiryukov]

Related: #30334

[ocean90]

#36963 was marked as a duplicate.

[nigro.simone]

Very simple way for support old php version without __DIR__ (< 5.3.0) is add in index.php:

<?php
if( !defined('__DIR__') ){
    define('__DIR__', dirname(__FILE__));
}

and now is possible and safe replace everywhere dirname(__FILE__) with __DIR__

this work without problem (tested my self).

[jdgrimes]

Replying to nigro.simone:

Very simple way for support old php version without __DIR__ (< 5.3.0) is add in index.php:

<?php
if( !defined('__DIR__') ){
    define('__DIR__', dirname(__FILE__));
}

and now is possible and safe replace everywhere dirname(__FILE__) with __DIR__

this work without problem (tested my self).

This will only work for files in that one directory. __DIR__ won't be magic, and so it is really not any use for us. We can already use ABSPATH or other constants. In fact, that's what we already do. The only place that we really use dirname( __FILE__ ) in core is in files that are entry-points of the application. We use that to include the bootstrap, and then use ABSPATH and other constants after that.

For plugins, the solution is for them to define their own constants if they don't want to use dirname( __FILE__ ) in every place.

[nigro.simone]

ok, this is a "maybelater" when minimal php version of wordpress will be PHP 5.3

Side note: PHP 5.2 is out-date and unsafe.