Need docs on Btree

[Billy Davis]

We are porting an old B-Tree application from FreeBSD to RedHat 7.3, but we cannot find any information on the B-Tree read and write commands.  'man btree' yeilds info on 'dbopen'.  'man read' and 'man write' have nothing to do with B-Tree.  Can anybody help us find info on B-Tree under RedHat?   Thanks, BD