PHP_OUTPUT_HANDLER_REMOVABLE

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

PHP_OUTPUT_HANDLER_REMOVABLE — Controls whether an output buffer created by ob_start can be removed before the end of the script or when calling ob_end_clean, ob_end_flush, ob_get_clean or ob_get_flush.

PHP_OUTPUT_HANDLER_REMOVABLE = 64;