On Fri, 23 Oct 2009, Pritpal Bedi wrote:
Hi,
> This is the code how object is created and GC applied.
> This code compiles perfect but receive GPF at its first invocation.
It's expected behavior. You are storing pointer to temporaryGC table
located on C stacks which is overload immediately by other functions
calls.
> //---------------------------------------//
> HB_GARBAGE_FUNC( Q_release )
> {
> QGC_POINTER * p = ( QGC_POINTER * ) Cargo;
> if( p && p->ph )
> {
> p->func( p->ph );
> }
> }
>
> const HB_GC_FUNCS QT_gcFuncs =
> {
> Q_release,
> hb_gcDummyMark
> };
>
> HB_GC_FUNCS gcFuncs( void )
> {
> return QT_gcFuncs;
> }
Should be:
const HB_GC_FUNCS * gcFuncs( void ) { return &QT_gcFuncs; }
> void * hbqt_gcpointer( int iParam )
> {
> HB_GC_FUNCS qt_gcFuncs = gcFuncs();
> QGC_POINTER * p = ( QGC_POINTER * ) hb_parptrGC( &qt_gcFuncs, iParam );
Should be:
void * hbqt_gcpointer( int iParam )
{
QGC_POINTER * p = ( QGC_POINTER * ) hb_parptrGC( gcFuncs(), iParam );
> /////////////////// I cannot reach past this point ///////////////
> if( p && p->ph )
> {
> return p->ph;
> }
> else
> {
> return hb_parptr( iParam );
This line is a bug which makes all other code unusable, i.e. it fully
breaks QPointer<> class functionality.
> }
> }
>
> //--------------------------------------------------//
>
> QT_G_FUNC( release_QMainWindow )
> {
> void * ph = ( void * ) Cargo;
> if( ph )
> {
> const QMetaObject * m = ( ( QObject * ) ph )->metaObject();
> if( ( QString ) m->className() != ( QString ) "QObject" )
This condition is something what I do not understand at all.
If some other code is buggy and can activate this destructor for
wrong objects then such code should be fixed instead of adding
workarounds for bugs.
> {
> delete ( ( QMainWindow * ) ph );
> ph = NULL;
> }
> }
> }
> Where is the error ?
See above. Few things can cause GPF in such code though probably
gcFuncs() usage was the 1-st reason.
I strongly suggest to encapsulate all classes in separate files
with separate destructors without and tricks with explicit casting
and with public functions to retrieve object pointers from HVM items
and/or parameters.
best regards,
Przemek
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