The method FileSize returns the size of the file AFile on the FTP server.
The function returns the following error codes:
0 ... everything is OK
-1 ... cannot find AFile
-2 ... not connected
Hint:
Most FTP servers are Unix-based. Thus the path to the file (AFile) normally uses slashes (/) instead of backslashes (\) to separate directories. Failing to use the correct separation character will result in an error (-1).