typedef struct { ... } SilcAttributeObjPN;

    SILC_ATTRIBUTE_PHONE_NUMBER type object.  The caller must free the
    phone number string inside the structure.

    typedef struct SilcAttributeObjPNStruct {
      SilcAttributePNFormat format; /* Phone number format */
      char *number;                 /* Phone number */
    } SilcAttributeObjPN;