PK_ATTDEF_register_cb   

PK_ERROR_code_t PK_ATTDEF_register_cb
(
--- received arguments ---
PK_ATTDEF_t                      attdef,    --- attribute definition
const PK_ATTDEF_callback_fns_t  *callbacks, --- callback functions
const PK_ATTDEF_register_cb_o_t *options    --- options
)


This function registers a set of callback functions to be called when entities
with attributes with definition 'attdef' undergo certain events.


The callback function will only be called if it is not NULL, and if the
corresponding logical flag, as set by PK_ATTDEF_set_callbacks, is
PK_LOGICAL_true. Calling this function does not alter the values of these
flags, which are initialised to PK_LOGICAL_false.

If the callback_type is PK_ATTDEF_callback_normal_c, which is the default,
then the attribute processing is performed by the callback function.
Registering this type of attribute callback function will disable tag
persistence within the Parasolid session. Please consider carefully whether
a read-only callback would be more appropriate.

If the callback type is PK_ATTDEF_callback_read_only_c, then Parasolid will
perform the standard attribute processing, depending on the attribute type.
The callback function must not modify any attributes or change the model in
any other way. Registering a read-only callback function does not disable tag
persistence.

See here for more information.