Observe the following rules when specifying length values:
All length values for variable-length records must include 4 bytes for the Record Descriptor Word.
The l1, l2, and l3 values must represent the maximum record lengths and the l4 value must represent the minimum record length. If MFX encounters a record which exceeds the maximum length or is shorter than the minimum length, the application will either terminate abnormally or produce unpredictable results.