Description:
------------
The documentation on functions (http://www.php.net/manual/en/language.functions.php) says:
"In PHP 3, functions must be defined before they are referenced. No such requirement exists since PHP 4. Except when a function is conditionally defined..."

I don't understand why the following code (in three different files BTW) doesn't work as expected. It doesn't seem to be conditionally defined.

Tested with PHP 4.4.4-CLI, PHP 5.2.1, PHP 5.2.2.

I am openminded that this may not be a bug but I can't seem to find an explanation.



Reproduce code:
---------------
FILE a.php:

<?php

error_reporting(E_ALL | E_NOTICE);

echo "FILE 'a.php'\n";

if (function_exists('test')) {
    echo test();
}
else {
    echo "function 'test()' doesn't exist!\n";
}

require 'b.php';

?>

------

FILE b.php

<?php

echo "FILE 'b.php'\n";

require 'c.php';

?>

------

FILE c.php

<?php

echo "FILE 'c.php'\n";

function test()
{
    return "function test() was called!\n";

}

?>


Expected result:
----------------
SIGNIFICANT expected result: 'function test() was called!' is echoed. Other output is for debugging.



Actual result:
--------------
Actual result: 'function 'test()' doesn't exist!' is echoed.