Read number of records written to the data file.

The LOF function returns the number of records written to the data file.

Set fileno to the value specified when opening the data file.

Check number of records written to the data file

  private SNO$
  private QTY$
  private BARDATA$
  private record%

  open "TESTDATA.DAT" as #1                       ' open data file
  field #1, 3 as SNO$, 5 as QTY$, 13 as BARDATA$  ' define fields
  
  record% = lof(#1)                               ' read number of records written
  close #1