pre_wp_nav_menu filter-hook . WP 3.9.0

Filters whether to short-circuit the wp_nav_menu() output.

Returning a non-null value to the filter will short-circuit wp_nav_menu(), echoing that value if $args->echo is true, returning that value otherwise.

Usage

add_filter( 'pre_wp_nav_menu', 'filter_function_name_2902', 10, 2 );
function filter_function_name_2902( $output, $args ){
	// filter...

	return $output;
}

$output(string/null)

Nav menu output to short-circuit with.
Default: null

$args(stdClass)

An object containing wp_nav_menu() arguments.

Where the hook is called

$nav_menu = apply_filters( 'pre_wp_nav_menu', null, $args );

Where the hook is used (in WP core)