The behavior of unset() inside of a function can vary depending on what type of variable you are attempting to destroy.
If a globalized variable is unset() inside of a function, only the local variable is destroyed. The variable in the calling environment will retain the same value as before unset() was called.
Example
<?php
function destroy_foo()
{
global $foo;
unset($foo);
}
$foo = ‘bar’;
destroy_foo();
echo $foo;
?>
