Find the next data block of a given type and subtype
void * PtFindNextData( PtDataHdr_t **ptr, PtDataHdr_t *data, long type, long subtype, long *len, PtDataHdr_t **_node );
This function finds the next data block, from data_node, that matches the type and subtype provided. If data_node is NULL, the first instance of data that matches the type and subtype provided is found. If type is 0, any type will match. If subtype is -1, any subtype will match.
If _node is provided, it's set to point to the data_node that contained the returned data in order to be able to continue the search from that node. If len is provided, it's set to the length of the data item as set when the data was originally added to the chain.
A pointer to the data, or NULL if no matching data was found.
PtAddData(), PtFindData(), PtRemoveData(), PtUnlinkData()