A have a unit (uSafeVar) with an object. The object has a property "data" of the type "SafeVar_typ"

If I do this it works (wSafeVar is called)

var
  p:SafeVar_typ;
begin
  p.d:=111;
  SafeVar.data:=p;
end

If I do this it dos not work but it compiles (wSafeVar is not called)

begin
  SafeVar.data.d:=111;
end;
If I do a read like this ( after the line SafeVar.data.d:=111;)
Writeln(SafeVar.data.d);
the output is 111

The compiler is
Free Pascal Compiler version 2.2.2 [2008/08/26] for arm

Of course I could create a property fore every variable I want to save, but in the real program it is a big record, so I thought this was a smart way to get around this. Is it in fact an error that it compiles?

Carsten

--------------------------------------------------------------------------
Unit uSafeVar;
{$mode objfpc}
Interface

Uses
sysutils,

  Classes;

Type
  SafeVar_typ = packed record
      d:byte;
  end;
  TSafeVar=class(TObject)
    Private
      hSafeVar:SafeVar_typ;
      f:file of SafeVar_typ;
      Procedure wSafeVar(data:SafeVar_typ);
    Public
      constructor create;
      destructor destroy; override;
      property data:SafeVar_typ read hSafeVar write wSafeVar;
    Published
  end;
var
  SafeVar:TSafeVar;
implementation
constructor TSafeVar.create;
Begin
  inherited Create;
  fillchar(hSafeVar,sizeof(SafeVar_typ),chr(0));
  assign(f,SafeVar_dat);
  if fileexists(SafeVar_dat) then
  begin
    reset(f);
    read(f,hSafeVar);
  end else
  begin
    rewrite(f);
    Write(f,hSafeVar);
  end;
End;
destructor TSafeVar.destroy;
Begin
  inherited destroy;
  close(f);
End;
Procedure TSafeVar.wSafeVar(data:SafeVar_typ);
Begin
  hSafeVar:=data;
  seek(f,0);
  Write(f,data);
End;
initialization
  SafeVar:=tSafeVar.create;
finalization
  SafeVar.free;
End.
------------------------------------------

Here the Data setter is called, ie, wSafeVar, because you are assigning a new value to it.

Here the Data getter is called, ie, hSafeVar, because you are reading a value from it.

Use a function as a getter instead of a class member. Btw getters and setters have not the same syntax, you need to create two different methods.

Was it this you meant? Now I cannot compile. If I change rSafeVar (In the property declaration) to hSafeVar it compiles.

Carsten

-------------------------------------------------
program safevartest;
{$mode objfpc}

Uses
sysutils; {System}

Type
  SafeVar_typ = packed record
      week:byte;
  end;
  TSafeVar=class(TObject)
    Private
      hSafeVar:SafeVar_typ;
      Procedure wSafeVar(data:SafeVar_typ);
      Function rSafeVar(data:SafeVar_typ):SafeVar_typ;
    Public
      constructor create;
      destructor destroy; override;
      property data:SafeVar_typ read rSafeVar write wSafeVar;
    Published
  end;
var
  SafeVar:TSafeVar;
constructor TSafeVar.create;
Begin
  inherited Create;
  fillchar(hSafeVar,sizeof(SafeVar_typ),chr(0));
End;
destructor TSafeVar.destroy;
Begin
  inherited destroy;
End;
Procedure TSafeVar.wSafeVar(data:SafeVar_typ);
Begin
  WriteLn('Write');
End;
Function TSafeVar.rSafeVar(data:SafeVar_typ):SafeVar_typ;
Begin
  WriteLn('Read');
End;
Begin
  SafeVar:=TSafeVar.create;
  SafeVar.data.week:=1;
  SafeVar.free;
End.
Med venlig hilsen
Carsten Bager

BEAS A/S
Brørupvænget 10
DK-7650 Bøvlingbjerg
Tlf. : +45 9788 5222 Fax : +45 9788 5434
www.beas.dk

Change to

       Function rSafeVar: SafeVar_typ;

Change to Function rSafeVar: SafeVar_typ;

Joao Morais

Sorry about that. I pasted the wrong code in the email. I have already changed that. It does still not compile after the change. Carsten

Med venlig hilsen
Carsten Bager

BEAS A/S
Brørupvænget 10
DK-7650 Bøvlingbjerg
Tlf. : +45 9788 5222 Fax : +45 9788 5434
www.beas.dk