With DECC$FIXED_LENGTH_SEEK_TO_EOF enabled, lseek, fseeko, and
    fseek with the direction parameter set to SEEK_END will position
    relative to the last byte in the file for files with fixed-length
    records.

    With DECC$FIXED_LENGTH_SEEK_TO_EOF disabled, lseek, fseek, and
    fseeko when called with SEEK_EOF on files with fixed-length
    records, will position relative to the end of the last record
    in the file.