[UPHPU] require_once vs. class_exists

[Lonnie Olson]

On Fri, 2008-04-18 at 09:13 -0700, Rusty Keele wrote:
> Hi,
> 
>   Which is a better approach to use:
>   
>   1. require_once('path/to/class.php');
> 
>   or
> 
>   2. if(!class_exists('path/to/class.php')) require('path/to/class.php');
> 
>   I have been using the first approach in all my files where I need to instantiate a specific class, but I am wondering if the second approach is more efficient?  Are there any benefits to using the second approach - such as less caching of objects - or do these two statements do the same thing?

There is also a 3rd way... Autoloading.
http://us2.php.net/autoload
You can write your own custom __autoload function to require the files
you need if a class doesn't exists.  It is very similar to #2, but can
automate it for all classes.

--lonnie