ob_get_level

(PHP 4 >= 4.2.0, PHP 5)

ob_get_level - Return the nesting level of the output buffering mechanism

Описание

int ob_get_level ( void )

This will return the level of nested output buffering handlers or zero if output buffering is not activated.

Смотрите также also ob_start() and ob_get_contents().

Описание на ru2.php.net
Описание на php.ru