Did you know what the function register_shutdown_function does in PHP? The manual defines this function as :

Registers the function named by function to be executed when script processing is complete.

This function runs at the end of any script execution – it also runs if your script exits prematurely due to some errors. This is a useful function to catch such exceptions in your script. Eirik Hoem’s written an article on this function over at his blog, where he shows an example on how to trap a premature end of script due to a fatal error:
<?php
$clean = false;
function shutdown_func(){
global $clean;
if (!$clean){
die("not a clean shutdown");
}
}
register_shutdown_function("shutdown_func");
$a = 1;
$a = new FooClass(); // will fail with fatal
$clean = true;
?>

Read Eric’s Article at : Dying with grace – PHP’s register_shutdown_function