- function_exists: documentation ( source)
- ini_get: documentation ( source)
<?php
// Works fine
$test = ( function_exists('apc_fetch') || ini_get('apc.enabled') );
// Fail with "Call to undefined function function_exists()"
$test = ( false || function_exists('apc_fetch') );
// Works fine because true do lazy check in OR
$test = ( true || function_exists('apc_fetch') );
// Fail with "Call to undefined function function_exists()"
$test = ( false || function_exists('apc_fetch') );