<p>I have an app that is failing on the install. The vendor says I probably have ini_set() disabled. How can I check this?</p>

You might want to take a look at the CHANGEABLE directives in php.ini:
http://us3.php.net/manual/en/ini.php#ini.list
In regard to verify whether an ini_set function worked, you can check the return value to make certain that it worked:
http://us3.php.net/manual/en/function.ini-set.php
The code would look something like this:
```
```
<?php
     if(ini_set('error_reporting', 'ALL') === false)
     {
         // Perform failure handling logic
     }
?>
```
```