+
+/**
+ * Determine whether a meta key is protected
+ *
+ * @since 3.1.3
+ *
+ * @param string $meta_key Meta key
+ * @return bool True if the key is protected, false otherwise.
+ */
+function is_protected_meta( $meta_key, $meta_type = null ) {
+ $protected = ( '_' == $meta_key[0] );
+
+ return apply_filters( 'is_protected_meta', $protected, $meta_key, $meta_type );
+}
+
+/**
+ * Sanitize meta value
+ *
+ * @since 3.1.3
+ *
+ * @param string $meta_key Meta key
+ * @param mixed $meta_value Meta value to sanitize
+ * @param string $meta_type Type of meta
+ * @return mixed Sanitized $meta_value
+ */
+function sanitize_meta( $meta_key, $meta_value, $meta_type = null ) {
+ return apply_filters( 'sanitize_meta', $meta_value, $meta_key, $meta_type );
+}
+