Only variables can be passed by reference

Question

I had the bright idea of using a custom error handler which led me down a rabbit hole.

Following code gives (with and without custom error handler): Fatal er

Answer 1

array_pop() tries to change that value which is passed as parameter. Now in your second example this is the return value from array_slice(). In engine terms this is a "temporary value" and such a value can't be passed by references. what you need is a temporary variable:

function foo(){
    $a=explode( '/' , 'a/b/c');
    $b=array_slice($a,-2,1);
    $c=array_pop($b);
    return $c;
}
print_r(foo());

Then a reference to $b can be passed to array_pop(). See http://php.net/references for more details on references.