If like me you thought ini_restore() would restore to the most recent setting rather than the startup value, you could use this.

<?php

/**
 * Executes a function using a custom PHP configuration.
 * 
 * @param array $settings A map<ini setting name, ini setting value>.
 * @param callable $doThis The code to execute using the given settings.
 * @return mixed Returns the value returned by the given callable.
 */
function ini_using_do(array $settings, callable $doThis){
    foreach($settings as $name => $value){
        $previousSettings[$name] = ini_set($name, $value);
    }
    $returnValue = $doThis();
    if(isset($previousSettings)){
        foreach($previousSettings as $name => $value){
            ini_set($name, $value);
        }
    }
    return $returnValue;
}

?>