MODULE IOChanSeekProg;
(* IOChan positioning: Position / Seek / Rewind on a file channel.
   Write 6 bytes, reopen, seek and read back.  Exit 15. *)
IMPORT IOChan, Strings;
VAR ExitCode : INTEGER;
VAR f : IOChan.ChanId;
VAR name, line : ARRAY [0 .. 63] OF CHAR;
BEGIN
  Strings.Assign("gen_ssa/_iochanseek.txt", name);

  f := IOChan.OpenWrite(name);
  IOChan.WriteString(f, "abc");
  IOChan.WriteString(f, "def");
  IF IOChan.Position(f) = 6 THEN
    ExitCode := ExitCode + 1
  ELSE ExitCode := 100 END;
  IOChan.Close(f);

  f := IOChan.OpenRead(name);
  IF IOChan.ReadChar(f) = "a" THEN ExitCode := ExitCode + 0 END;
  IF IOChan.ReadChar(f) = "b" THEN ExitCode := ExitCode + 0 END;
  IF IOChan.Position(f) = 2 THEN
    ExitCode := ExitCode + 2
  ELSE ExitCode := 101 END;
  IF IOChan.Rewind(f) THEN
    IF IOChan.ReadChar(f) = "a" THEN ExitCode := ExitCode + 0 END;
    IF IOChan.Position(f) = 1 THEN ExitCode := ExitCode + 4 END;
    IF IOChan.Seek(f, 3) THEN
      IOChan.ReadString(f, line);
      IF line = "def" THEN ExitCode := ExitCode + 8 ELSE ExitCode := 102 END
    END
  END;
  IOChan.Close(f)
END IOChanSeekProg.