BtrvGetPrev
BtrvGetPrev (DataVar,Key,Handle)
BtrvGetPrev goes to the previous record of the file based on the key
number that you pass and reads the record into DataVar. This allows you
to access that database in the sorted order of the key. DataVar is a
MarxMenu variable and the data read creates an array of the fields
stored on disk.
Result Codes:
6 - Invalid Key Number
7 - Different Key Number
9 - End of File
