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filter is not described

add_(meta_type)_metadata filter-hook . WP 3.1.0

Filters whether to add metadata of a specific type.

The dynamic portion of the hook, $meta_type, refers to the meta object type (comment, post, term, or user). Returning a non-null value will effectively short-circuit the function.


add_filter( 'add_(meta_type)_metadata', 'filter_function_name_1901', 10, 5 );
function filter_function_name_1901( $check, $object_id, $meta_key, $meta_value, $unique ){
	// filter...

	return $check;
Whether to allow adding metadata for the given type.
Object ID.
Meta key.
Meta value. Must be serializable if non-scalar.
Whether the specified meta key should be unique for the object. Optional.
Default: false


Since 3.1.0 Introduced.

Where the hook is called

wp-includes/meta.php 72
$check = apply_filters( "add_{$meta_type}_metadata", null, $object_id, $meta_key, $meta_value, $unique );

Where the hook is used (in WP core)

wp-includes/default-filters.php 111
add_filter( 'add_term_metadata', 'wp_check_term_meta_support_prefilter' );
wp-includes/ms-default-filters.php 61
add_filter( 'add_blog_metadata', 'wp_check_site_meta_support_prefilter' );