DOS Fn 23H: Query File Size via FCB

                                                         Compatibility: 1.0+ 
 Expects: AH    23H
          DS:DX address of an opened FCB
 Returns: AL    0    if file was found
                0ffH if file was not in current directory
    Info: Sets the randomRec field of the FCB to indicate how many records
          of recSize bytes are contained in the file.

          Be sure to set recSize before calling.  If you set recSize to 1,
          then RandomRec will hold a 4-byte value of file size in bytes.

   Notes: ■ You may find it easier to determine the file size by using 3dH
            Open Handle followed by 42H Lseek Handle (with AL=2).

          ■ A faster way is to use fn 4eH (find file).

          ■ The fastest way may be to read the directory.  See INT 25H.

See Also: Directory and File Functions
          FCB File I/O
          DOS Functions