what happens with memory when I throw an exception?

Question

This is the code (just a simplification of a real problem):

<?php
echo memory_get_usage() . "\n";
function f() {
    throw new Exception();
}
function foo() {
    try {
        f();
    } catch (Exception $e) {
    }
}
foo();
echo memory_get_usage() . "\n";

This is the output (PHP 5.3):

630680
630848

What happened with memory (168 bytes lost)? The exception object is not destroyed? Please, help! Thanks

Answer 1

The exception object is destroyed. What's more likely, is that you have output buffering on, and the added 168 bytes is from the echoed this is a test\n being stored in the buffer. An exception will use significantly more than 168bytes (as it stores a backtrace, and other information).