[fpc-pascal] TObject

[Carsten Bager]

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.
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