This function will send the contents of the topmost output buffer (if any) and turn this output buffer off. If you want to further process the buffer's contents you have to call ob_get_contents() before ob_end_flush() as the buffer contents are discarded after ob_end_flush() is called.
Note: This function is similar to ob_get_flush(), except that ob_get_flush() returns the buffer as a string.
Returns TRUE on success or FALSE on failure. Reasons for failure are first that you called the function without an active buffer or that for some reason a buffer could not be deleted (possible for special buffer).