seek/2 seeks to the end of the file when Offset is instantiated to end_of_file.
seek/2 has no effect on the null stream, it always succeeds.
Success: seek( 0,null). % does not modify, only succeeds [eclipse]: open(file1,update,s), write(hello,s), > seek(3,s), read(T,s), close(s). T = lo yes. Error: seek( Offset,7). (Error 4). seek("7", 2). (Error 5). seek(7, -1). (Error 6). seek( 0,input). (Error 192). seek(-1, 0). (Error 193). % does not exist