note 44138 added to function.imap-headers

While I have little doubt that the function works as documented, the test code, as written, is completely invalid. You can't just subtract two restults from microtime. Microtime returns a string with: ".microseconds seconds" in it. IE, it begins with a period (.) and then the microseconds, and then a space ( ) and then the seconds. You would need something more like: $start_time = microtime(); ;; code to be benchmarked here $end_time = microtime(); list($start_usec, $start_sec) = explode(' ', $start_time); list($end_usec, $end_sec) = explode(' ', $end_time); $delta = ($end_sec + $end_usec) - ($start_sec + $start_usec); echo "elapsed_time: $delta<BR>\n"; In the original source, the negative numbers indicate that the milliseconds portion of your ending time is LOWER than the milliseconds portion of the starting time -- Which means that the seconds portion has "turned over" to the next second -- or possibly several seconds later. It could even be HOURS later, though I daresay you would have noticed that :-) ---- Manual Page -- http://www.php.net/manual/en/function.imap-headers.php Edit -- http://master.php.net/manage/user-notes.php?action=edit+44138 Delete -- http://master.php.net/manage/user-notes.php?action=delete+44138&report=yes Reject -- http://master.php.net/manage/user-notes.php?action=reject+44138&report=yes Search -- http://master.php.net/manage/user-notes.php