Checks if an end-of-file is reached when reading a file. May be used in conjunction with the ReadLine method to check if all lines have been read.
Returns 0 when the end of the file has not yet been reached, and 1 if it has been reached.
The required and case-insensitive alias is the alias of the file to be closed. This alias must previously have been assigned to a file at the time when the USFile.Open method was called. Alias is a regular name string that may or may not use the 'USFile.' prefix.