PHP_OUTPUT_HANDLER_CLEANABLE

PHP_OUTPUT_HANDLER_CLEANABLE is one of the accepted parameters for ob_start parameter #3 (optionally as a bitmask).

PHP_OUTPUT_HANDLER_CLEANABLE — Controls whether an output buffer created by ob_start can be cleaned by ob_clean. This flag does not control the behaviour of ob_end_clean or ob_get_clean.

PHP_OUTPUT_HANDLER_CLEANABLE = 16;