I'm flummoxed a bit. I recently upgraded from PHP 5.2 to 5.3 and my class files no longer autoload. I realize that 5.3 changed in that it now allows namespaces, but I haven't been able to find any resources on changes to autoloading. Is 5.3 backward compatible or are namespaces required? Or is there some PHP setting that I need to enable (I'm using XAMPP 1.7.2 as my localhost and haven't changed any of the default settings)? Ideally, I'd like to have my classes autoload in both 5.2 and 5.3.

Here's an example of the format I'm using for autoloading:

function __autoload($className) {
$className = str_replace('_', '/', $className);
require_once('includes/'.$className.'.php');
}
And the class:

class Example_Class_Two extends Example_Class_One {

function __construct(){
echo "I'm a function.";
}

}
I haven't made any changes to the code from when it worked in 5.2, but don't hesitate to point out the patently obvious because it may be that I'm missing something simple. Thanks!

I just tested auto loading on my local server (Apache 2.2 and PHP 5.3.1) and it appears to be working normally. Namespaces are not required, though if you are using them you should be careful which namespace your autoload function is defined under. Is your autoload function being called at all? Here is the code I used for testing:

PHP Code:

echo 'PHP Version: ' . phpversion() . '</br>';

function __autoload($classname)
{
    echo 'Loading class: ' . $classname . '</br>';
    eval("class $classname {
        function __construct()
        {
            echo '$classname';
        }
          }");
}

$foo = new Foo(); 


and the output:
PHP Version: 5.3.1
Loading class: Foo
Foo

It might be that it isn't being loaded at all. For some reason I'm not able to get any output from the file. Did anything change for require_once() for PHP 5.3?

So here's what it turned out to be: I never use short tags (<? ?>) and always use the full declaration (<?php ?>). For whatever reason, my autoloader file had short tags, which PHP 5.3 deprecated. I switched to the full declaration and bingo, it works!

Man, I've been staring at that for about three weeks.