[Gambas-devel] How to know if an object is allocated or freed ?

[Laurent Carlier]

Le Mardi 14 Décembre 2004 23:35, Daniel Campos a écrit :
> Mmmh... Once an object is freed its pointer becomes NULL, as GB.Unref()
> does it when reference count is zero... However if you have more than a
> pointer pointing to that "bad" object, may be you can try GB.Is()
>
> Regards,
>
> D. Campos
>
>

I store the object with :
static CBUFFER *Buff = NULL;

and the following code (Draw.Buffer(toto)) :
BEGIN_METHOD(DRAWING_buffer, GB_OBJECT buffer)

  Buff = VARG(buffer);
  if (GB.CheckObject((void *) Buff))
  {
    GB.Propagate();
  } 
  
END_METHOD

toto is redefined with toto =  Screen.Grab()

In Draw.Line it segfault :
BEGIN_METHOD(DRAWING_draw, GB_INTEGER X1; GB_INTEGER Y1; GB_INTEGER X2; 
GB_INTEGER Y2)

  Sint16 x1, y1;

  if (GB.CheckObject((void *) Buff))
  {
    GB.Propagate();
  } 
  x1 = VARG(X1);
  y1 = VARG(Y1);

  LastX = VARG(X2);
  LastY = VARG(Y2);

  lineColor(GETSURFACE(Buff), x1, y1, LastX, LastY, CColor);

END_METHOD

it segfault with GB.CheckObject((void *) Buff) as Buff doesn't seem to be NULL 
but only invalid !

-- 

Laurent Carlier