WordPress at a glance
filter is not described

dynamic_sidebar_has_widgets filter-hook . WP 1.0

This filter is documented in wp-includes/widget.php

Usage

add_filter( 'dynamic_sidebar_has_widgets', 'filter_function_name_4528', 10, 2 );
function filter_function_name_4528( $false, $index ){
	// filter...

	return $false;
}
$false
-
$index
-

Where the hook is called

dynamic_sidebar()
dynamic_sidebar_has_widgets
wp-includes/widgets.php 691
return apply_filters( 'dynamic_sidebar_has_widgets', false, $index );
wp-includes/widgets.php 836
return apply_filters( 'dynamic_sidebar_has_widgets', $did_one, $index );

Where in WP core the hook is used WordPress

wp-includes/widgets.php 124
add_filter( 'dynamic_sidebar_has_widgets', array( $this, 'tally_sidebars_via_dynamic_sidebar_calls' ), 10, 2 );