(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)
ob_get_clean — Get the contents of the active output buffer and turn it off
   This function calls the output handler
   (with the PHP_OUTPUT_HANDLER_CLEAN and
   PHP_OUTPUT_HANDLER_FINAL flags),
   discards it's return value,
   returns the contents of the active output buffer
   and turns off the active output buffer.
  
   ob_get_clean() will fail
   without an active output buffer started with the
   PHP_OUTPUT_HANDLER_REMOVABLE flag.
  
   ob_get_clean()
   will discard the contents of the active output buffer
   even if it was started without the
   PHP_OUTPUT_HANDLER_CLEANABLE flag.
  
This function has no parameters.
   Returns the contents of the active output buffer on success
   or false on failure.
  
    ob_get_clean() will return false
    but will not generate an E_NOTICE
    if there is no active output buffer.
   
   If the function fails it generates an E_NOTICE.
  
Example #1 A simple ob_get_clean() example
<?php
ob_start();
echo "Hello World";
$out = ob_get_clean();
$out = strtolower($out);
var_dump($out);
?>The above example will output:
string(11) "hello world"