'Follow up question'

[Rudolf Schubert]

Hi,

I'm digging a bit further into gm2 and I think there is a problem with
SeqFile.OpenAppend. Instead of appending data when using IOChan.RawWrite
writing data starts from the beginning of the file. Here is my short
test program:


MODULE port_test5_gm2;
    
FROM ChanConsts IMPORT
  OpenResults, old, raw, write;
FROM IOChan IMPORT
  ChanId, RawWrite;
FROM StdChans IMPORT
  StdOutChan; 
FROM SYSTEM IMPORT
  ADR;
IMPORT StreamFile;
IMPORT SeqFile;

    
PROCEDURE IoTest();
  CONST
    arr_len=                    16;

  TYPE
    arr_type=                   ARRAY[0..arr_len-1] OF CHAR;

  VAR
    cid_file:                   ChanId;
    file_name:                  arr_type;
    res:                        OpenResults;
    array:                      arr_type;
    c1:                         CARDINAL;

  BEGIN                         (* PROCEDURE IoTest *)
    file_name:='test_data';

    (* initialize array for first write operation with upper case letters *)
    FOR c1:=0 TO arr_len-1 DO
      array[c1]:=CHR(65+c1);
    END;                        (* FOR c1 *)

    (* write arr_len characters to file *)
    StreamFile.Open(cid_file, file_name, write+old+raw, res);
    IF res=opened THEN
      RawWrite(cid_file, ADR(array), arr_len);
      StreamFile.Close(cid_file);
    END;                        (* IF res=opened *)

    (* initialize array for second write operation with lower case letters *)
    FOR c1:=0 TO arr_len-1 DO
      array[c1]:=CHR(65+32+c1);
    END;                        (* FOR c1 *)

    (* append (arr_len DIV 2) characters to file *)
    SeqFile.OpenAppend(cid_file, file_name, write+old+raw, res);
    (*
    SeqFile.OpenWrite(cid_file, file_name, write+old+raw, res);
    *)
    IF res=opened THEN
      RawWrite(cid_file, ADR(array), arr_len DIV 2);
      SeqFile.Close(cid_file);
    END;                        (* IF res=opened *)
  END IoTest;


BEGIN                           (* MODULE port_test5_gm2 *)
  IoTest();
END port_test5_gm2.


If I use SeqFile.OpenWrite instead of SeqFile.OpenAppend the result
is the same. So ist seems SeqFile.OpenAppend behaves exactly as
SeqFile.OpenWrite which sould not be the case.

This is with the latest version of gm2 under Debian sid:
gm2 (GCC) 13.0.1 20230414 (experimental)


BR

Rudolf

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