+<!-- ##### FUNCTION gras_datadesc_declare_union_append ##### -->
+<para>
+
+</para>
+
+@union_type:
+@name:
+@field_type:
+@Returns:
+
+
+<!-- ##### FUNCTION gras_datadesc_declare_union_close ##### -->
+<para>
+
+</para>
+
+@union_type:
+
+
+<!-- ##### FUNCTION gras_datadesc_cb_set_pre ##### -->
+<para>
+
+</para>
+
+@type:
+@pre:
+
+
+<!-- ##### FUNCTION gras_datadesc_cb_set_post ##### -->