Originally, FairCom DB filters were implemented as table based, such that once a filter was activated, all ISAM contexts would share the same condition. This situation caused some odd behavior and prevented c-treeDB record handles from setting their own filters to operate on table records.
A modification was introduced to the filter logic to permit the setting of filters for each independent c-tree ISAM context and c-treeDB was changed for the new filter condition. Each c-treeDB record handle can have its own filter and operate independently on the table records.
Since the filters should now be defined on a record basis, table based filters are no longer supported and c-treeDB returns CTDBRET_NOTSUPPORTED.
c-treeDB C++ API