From QB64.org wiki
The EOF function indicates that the end of a file has been reached.
- endReached%% = EOF([#]fileNumber&)
- fileNumber& is the number of the file being read. # is not required.
- Returns 0 until the end of a file. This avoids a file read error.
- Returns -1 (true) at the end of the file.
- Note that GET can return invalid data at the end of a file. Read EOF after a GET operation to see if the end of the file has been reached and discard last read.