registered_meta_key_exists()

registered_meta_key_exists() — Checks if a meta key is registered.

Inputs: $object_type (string): Type of object metadata is for. Accepts ‘blog’, ‘post’, ‘comment’, ‘term’, ‘user’, or any other object type with an associated meta table. $meta_key (string): Metadata key. $object_subtype (string): Optional. The subtype of the object type. Default empty string.

Returns bool: True if the meta key is registered to the object type and, if provided, the object subtype. False if not.