WordPress at a glance
filter is not described

the_posts filter-hook . WP 1.5.0

Filters the array of retrieved posts after they've been fetched and internally processed.

Usage

add_filter( 'the_posts', 'filter_function_name_2974', 10, 2 );
function filter_function_name_2974( $posts, $this ){
	// filter...

	return $posts;
}
$posts(array)
The array of retrieved posts.
$this(WP_Query)
The WP_Query instance (passed by reference).

Where the hook is called

WP_Query::get_posts()
wp-includes/class-wp-query.php 2982
$this->posts = apply_filters_ref_array( 'the_posts', array( $this->posts, &$this ) );

Where the hook is used (in WP core)

wp-includes/default-filters.php 242
add_filter( 'the_posts', '_close_comments_for_old_posts', 10, 2);