WordPress at a glance
filter is not described

found_posts filter-hook . WP 2.1.0

Filters the number of found posts for the query.

Usage

add_filter( 'found_posts', 'filter_function_name_829', 10, 2 );
function filter_function_name_829( $found_posts, $this ){
	// filter...

	return $found_posts;
}
$found_posts(int)
The number of posts found.
$this(WP_Query)
The WP_Query instance (passed by reference).

Where the hook is called

WP_Query::set_found_posts()
wp-includes/class-wp-query.php 3054
$this->found_posts = apply_filters_ref_array( 'found_posts', array( $this->found_posts, &$this ) );

Where the hook is used (in WP core)

Does not used.