Detect browser connection closed in PHP

Question

Does anyone know if it is possible to detect whether the browser has closed the connection during the execution of a long PHP script, when using apache

Answer 1

In at least PHP4, connection_aborted and connection_status only worked after the script sent any output to the browser (using: flush() | ob_flush()). Also don't expect accurately timed results.

It's mostly useful to check if there is still someone waiting on the other side.