Hello, Carl.
I lost a full day trying to get the following program to work (FPC v1.0.5):

============================================================
{$H+} { Huge strings }
{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
// {$DEFINE NO_BUG}
program bug;
var
  S, S2, S3: String;
  i1: Integer;
begin
    i1:=13;
    S:='This is text';
    S2:=Copy(S, 1, i1-1);
      {$IFDEF KYLIX}
         WriteLn( 'S2 RefCount=', LongInt(Pointer(Integer(S2)-8)^) );
      {$ELSE}
         WriteLn( 'S2 RefCount=', LongInt(Pointer(Integer(S2)-4)^) );
      {$ENDIF}
    S3:='';
    S3:=S2;
    S:='Quick brown fox';
    WriteLn( '===============================');
      {$IFDEF KYLIX}
         WriteLn( 'S2 RefCount=', LongInt(Pointer(Integer(S2)-8)^) );
         WriteLn( 'S3 RefCount=', LongInt(Pointer(Integer(S3)-8)^) );
      {$ELSE}
         WriteLn( 'S2 RefCount=', LongInt(Pointer(Integer(S2)-4)^) );
         WriteLn( 'S3 RefCount=', LongInt(Pointer(Integer(S3)-4)^) );
      {$ENDIF}
      {$IFDEF NO_BUG}
        WriteLn( 'S2=', ShortString(S2));
        WriteLn( 'S3=', ShortString(S3));
      {$ELSE}
        WriteLn( 'S2=',             S2);
        WriteLn( 'S3=',             S3);
      {$ENDIF}
    S2:=Copy(S, 1, i1-1);
    WriteLn( '===============================');
      {$IFDEF KYLIX}
         WriteLn( 'S2 RefCount=', LongInt(Pointer(Integer(S2)-8)^) );
         WriteLn( 'S3 RefCount=', LongInt(Pointer(Integer(S3)-8)^) );
      {$ELSE}
         WriteLn( 'S2 RefCount=', LongInt(Pointer(Integer(S2)-4)^) );
         WriteLn( 'S3 RefCount=', LongInt(Pointer(Integer(S3)-4)^) );
      {$ENDIF}
      {$IFDEF NO_BUG}
        WriteLn( 'S2=',ShortString(S2));
        WriteLn( 'S3=',ShortString(S3));
      {$ELSE}
        WriteLn( 'S2=',             S2);
        WriteLn( 'S3=',             S3);
      {$ENDIF}
end.
============================================================

After debugging, the following change was found in RTL: ========================================================================= -+- 1.0.5-010314/rtl/inc/astrings.inc Wed Jan 31 05:10:24 2001 +++ 1.0.5-010619/rtl/inc/astrings.inc Wed Jun 13 03:38:47 2001 @@ -1,5 +1,5 @@
{
- $Id: astrings.inc,v 1.1.2.7 2000/12/09 22:54:06 florian Exp $
+ $Id: astrings.inc,v 1.1.2.9 2001/06/16 03:51:50 carl Exp $ This file is part of the Free Pascal run time library. Copyright (c) 1999-2000 by Michael Van Canneyt,
member of the Free Pascal development team.
@@ -130,7 +130,7 @@
end;

-Procedure AnsiStr_Incr_Ref (Var S : Pointer);[Public,Alias:'FPC_ANSIST +Procedure AnsiStr_Incr_Ref ( S : PAnsiRec);[Public,Alias:'FPC_ANSISTR_ Begin

   If S=Nil then
     exit;

@@ -692,8 +692,33 @@

   Move (Buf[0],S[1],Len);

end;
...................
{
$Log: astrings.inc,v $
+ Revision 1.1.2.9 2001/06/16 03:51:50 carl
+ * bugfix of parameter ansistr_incr_ref which did not concord with x86 asm ========================================================================

But AnsiStr_Incr_Ref do not get right parameter if S is not Var.
And the following lines are broken after replacing Pointer to PAnsiRec:
  If PAnsiRec(S-FirstOff)^.Ref<=0 then exit;
  Inc(PAnsiRec(S-FirstOff)^.Ref);
In case of S:PAnsiRec this lines must be
  If PAnsiRec(Pointer(S)-FirstOff)^.Ref<=0 then exit;
  Inc(PAnsiRec(Pointer(S)-FirstOff)^.Ref);

After looking last FPC 1.0.5 updates, I do not see any changes that correct this problem.

Carl, can you explain your bugfix idea?

Regards,
Sergey Korshunoff

Hello, Carl. I lost a full day trying to get the following program to work

This bug was already detected, and should be already fixed meanwhile

Marco van de Voort wrote

> I lost a full day trying to get the following program to work This bug was already detected, and should be already fixed meanwhile

No, I've only just committed the fix. The reason for the change from Carl was to get the Pascal version of the addref() procedure to work. However, as you noticed, it was wrong. As of tomorrows' snapshot, everything should be fine again (if the snapshot creation works, because it failed last night)

Jonas