Hi!

Maybe I'd found a bug in gdbm.pp I'm running Linux (2.6.7) and fpc-1.9.4:

fpctest2 $ ./testgdbm2
Inserted string 1
Inserted string 2
Inserted string 3
Inserted string 4
Inserted string 5
Inserted string 6
Inserted string 7
Inserted string 8
Inserted string 9
Inserted string 10
Data for key 1 (string 7) : data for string 7
Data for key 2 (string 6) : data for string 6
Data for key 3 (string 5) : data for string 5
Data for key 4 (string 4) : data for string 4
Data for key 5 (string 10) : data for string 10
Data for key 6 (string 3) : data for string 3
Data for key 7 (string 2) : data for string 2
Data for key 8 (string 1) : data for string 1
Data for key 9 (string 9) : data for string 9
Data for key 10 (string 8) : data for string 8
An unhandled exception occurred at 0x0805B37C :
EAccessViolation : Access violation
$0805B37C

This seems to be a error in gdbm.pp:

Function DatumToString(Key : TDatum) : String;
begin
  SetLength(DatumToString,Key.dsize);
  If key.Dsize>0 then
    Move(key.dptr^,DatumToString[1],key.dsize);
  if key.dptrNil then
    cfree(Key.dptr);
end;
The function is called by function gdbm_nextkey(para1:PGDBM_FILE; Const
Para2 :string):string;

I'd changed the DatumToString() function to

Function DatumToString(Key : TDatum) : String;
begin
  if key.dptr  Nil then
  begin
    SetLength(DatumToString,Key.dsize);
    If key.Dsize>0 then
    Move(key.dptr^,DatumToString[1],key.dsize);
  { if key.dptrNil then }
    cfree(Key.dptr);
  end;
end;

This now works (but due to a lack of experience with this unit it may be wrong)

Anyone here who has the same error with testgdbm2.pp?

I will test next time I have my PC back the same on FreeBSD 5.x.

tia, Christian

I am not too sure, be I might suggest that instead of moving that test : *** if key.dptrNil then ***
before the line :
*** SetLength(DatumToString,Key.dsize); ***
you could move it *after* that line.

Because I understand that in case key.dptr is nil Move(key.dptr^,... is a mistake, but the setlength(... instruction might be better off if left as is. Removing it might have some bad side effect...

Hope that helps.
Regards.

En réponse à Christian Müllerke :

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Jérémie Lefrançois
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Altran Technologies