title: WPSC_UPDATE_META Function in PHP How too use it?
body: <p>Someone that's familiar with this know how to use it? I can't find any documentation on this function anywhere. and can this be used to update say for example the weight field and changing it from the default of pounds to options?</p>
  
  <p>I assume the proper setup would be something like this, bu I've no idea what goes in type.</p>
  
  <pre><code>wpsc_update_meta($post_id, 'weight', '3', $type); 
  wpsc_update_meta($post_id, 'weight_unit', 'ounce', $type);
  </code></pre>
  
  <p>Any ideas guys? The full function is listed below.</p>
  
  <pre><code>function wpsc_update_meta( $object_id = 0, $meta_key, $meta_value, $type, $global = false ) {
  global $wpdb;
  if ( !is_numeric( $object_id ) || empty( $object_id ) &amp;&amp; !$global ) {
      return false;
  }
  $cache_object_id = $object_id = (int) $object_id;
  
  $object_type = $type;
  
  $meta_key = wpsc_sanitize_meta_key( $meta_key );
  
  $meta_tuple = compact( 'object_type', 'object_id', 'meta_key', 'meta_value', 'type' );
  $meta_tuple = apply_filters( 'wpsc_update_meta', $meta_tuple );
  extract( $meta_tuple, EXTR_OVERWRITE );
  
  $meta_value = $_meta_value = maybe_serialize( $meta_value );
  $meta_value = maybe_unserialize( $meta_value );
  
  $cur = $wpdb-&gt;get_row( $wpdb-&gt;prepare( "SELECT * FROM `".WPSC_TABLE_META."` WHERE `object_type` = %s AND `object_id` = %d AND `meta_key` = %s", $object_type, $object_id, $meta_key ) );
  if ( !$cur ) {
      $wpdb-&gt;insert( WPSC_TABLE_META, array( 'object_type' =&gt; $object_type, 'object_id' =&gt; $object_id, 'meta_key' =&gt; $meta_key, 'meta_value' =&gt; $_meta_value ) );
  } elseif ( $cur-&gt;meta_value != $meta_value ) {
      $wpdb-&gt;update( WPSC_TABLE_META, array( 'meta_value' =&gt; $_meta_value), array( 'object_type' =&gt; $object_type, 'object_id' =&gt; $object_id, 'meta_key' =&gt; $meta_key ) );
  }
  wp_cache_delete( $cache_object_id, $object_type );
  
  if ( !$cur ) {
      return true;
  }
  }
  </code></pre>