(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)
ob_get_flush — Flush (send) the return value of the active output handler, return the contents of the active output buffer and turn it off
   This function calls the output handler
   (with the PHP_OUTPUT_HANDLER_FINAL flag),
   flushes (sends) it's return value,
   returns the contents of the active output buffer
   and turns off the active output buffer.
  
   ob_get_flush() will fail
   without an active output buffer started with the
   PHP_OUTPUT_HANDLER_REMOVABLE flag.
  
   ob_get_flush() will flush (send)
   the return value of the output handler
   even if the active output buffer was started without the
   PHP_OUTPUT_HANDLER_FLUSHABLE flag.
  
This function has no parameters.
   Returns the contents of the active output buffer on success
   or false on failure.
  
   If the function fails it generates an E_NOTICE.
  
Example #1 ob_get_flush() example
<?php
//using output_buffering=On
print_r(ob_list_handlers());
//save buffer in a file
$buffer = ob_get_flush();
file_put_contents('buffer.txt', $buffer);
print_r(ob_list_handlers());
?>The above example will output:
Array
(
    [0] => default output handler
)
Array
(
)