typedef struct PK_ATTDEF_callback_flags_s
    {
    PK_LOGICAL_t split_callback_on;
    PK_LOGICAL_t merge_callback_on;
    PK_LOGICAL_t delete_callback_on;
    PK_LOGICAL_t copy_callback_on;
    PK_LOGICAL_t transmit_callback_on;
    PK_LOGICAL_t receive_callback_on;
    }
    PK_ATTDEF_callback_flags_t;



This data structure holds logical flags which are set using
PK_ATTDEF_set_callback_flags. An attribute callback function will only be
called if it is not NULL, and its corresponding flag is set to PK_LOGICAL_true.