PHP: ob_clean - Manual

Description

void ob_clean ( void )

This function discards the contents of the output buffer.

This function does not destroy the output buffer like ob_end_clean() does.

ob_clean

cipri at php dot net
29-Jun-2004 09:54


In Re: to Anonymous at 14-Jan-2003.



You can't mimic the behaviour 100% by using that combination of function calls(ob_end_clean() && ob_start()), since outputhandlers may be defined already by the initial ob_start, which may not work as expected when called twice.

kouber at php dot net
11-May-2004 05:05


Although it is mentioned in the manual, you have to be careful when using output buffering in big cycles (such as mass mail sending scripts), because ob_clean() actually does not free any memory, and with each iteration the amount of memory allocated from your script will increase significantly. Instead of calling ob_clean() at the end of the cycle, you have to either use ob_get_clean(), which is a combination of ob_get_contents() and ob_end_clean(), or just ob_end_clean() to free the memory. Try the following test to see the difference:



<?php

for ($i=0; $i<10; $i++) {

  ob_start();



  echo "This is iteration $i: ";



  // * Don't do this!

  // $buf = ob_get_contents();

  // ob_clean();



  // * Use this instead:

  $buf = ob_get_clean();



  echo $buf;

  

  echo memory_get_usage()."\n";

}

?>

14-Jan-2003 08:23


As far as I can tell the only way to mimic ob_clean()'s behaviour on PHP < 4.2.0 is calling ob_end_clean() followed by ob_start().