WordPress at a glance
filter is not described

wp_cache_themes_persistently filter-hook . WP 3.4.0

Filters whether to get the cache of the registered theme directories.

Usage

add_filter( 'wp_cache_themes_persistently', 'filter_function_name_433', 10, 2 );
function filter_function_name_433( $cache_expiration, $cache_directory ){
	// filter...

	return $cache_expiration;
}
$cache_expiration(true/false)
Whether to get the cache of the theme directories.
Default: false
$cache_directory(string)
Directory to be searched for the cache.

Where the hook is called

search_theme_directories()
wp_cache_themes_persistently
WP_Theme::__construct()
wp_cache_themes_persistently
wp-includes/theme.php 446
if ( $cache_expiration = apply_filters( 'wp_cache_themes_persistently', false, 'search_theme_directories' ) ) {
wp-includes/class-wp-theme.php 194
self::$persistently_cache = apply_filters( 'wp_cache_themes_persistently', false, 'WP_Theme' );

Where the hook is used (in WP core)

Does not used.