Description:
------------
sprintf() will return a trailing NULL character under certain conditions. See code below.

Reproduce code:
---------------
<?php
    $blah = sprintf("%04d", -500);

    echo "$blah\n";

    // display ASCII code for each character of $blah
    for ($i = 0; $i < strlen($blah); $i++) {
        echo ord($blah{$i}) . "\n";
    }
?>


Expected result:
----------------
The code should output:
-500
45
53
48
48



Actual result:
--------------
On PHP v4.3.2 it outputs:
-500
45
53
48
48
0

Notice the NULL (0) character at the end.