On Fri, 23 Oct 2009, Pritpal Bedi wrote:
Hi,
> I am almost lost how to implement new GC structures
> under dynamic scenario of HBQT.
Just like me looking at hbqt code ;-)
> Can you guide in this direction?
I do not understand current hbqt code. It looks that it has three
different versions of code to manage pointers to objects and only
one is active. I'm afraid that it's hard for me to make any
modifications in this code so I updated code for one of QT class
(QPageSetupDialog). It's below.
Please note that release_QPageSetupDialog and s_gcQPageSetupDialog
are statics and only hbqt_par_QPageSetupDialog() is a public function
not a macro which returns pointer to QPageSetupDialog. Such version
gives very good encapsulation so you do not have to use any casting
which may hide very serious bugs and you do not have to worry that
pointer to different object is used by mistake. Inside GC block
QPointer< QPageSetupDialog > is stored so it will be automatically
cleared if object is released by other code.
I also suggest to define .prg classes in a little bit different way
which will be more efficient. In fact in Harbour and xHarbour INLINE
messages are two times slower then normal messages because they need
indirect EVAL() call. Anyhow it's a minor problem which can be easy
done later when the base version will work as expected.
best regards,
Przemek
/*** QPageSetupDialog.cpp ***/
[...]
static HB_GARBAGE_FUNC( release_QPageSetupDialog )
{
QPointer< QPageSetupDialog > * pObj = ( QPointer< QPageSetupDialog > * )
Cargo;
QPageSetupDialog * obj = * pObj;
if( obj )
{
*pObj = NULL;
delete obj;
}
}
static const HB_GC_FUNCS s_gcQPageSetupDialog =
{
release_QPageSetupDialog,
hb_gcDummyMark
};
QPageSetupDialog * hbqt_par_QPageSetupDialog( int iParam )
{
QPointer< QPageSetupDialog > * pObj = ( QPointer< QPageSetupDialog > * )
hb_parptrGC( &s_gcQPageSetupDialog, iParam );
QPageSetupDialog * obj = * pObj;
/* TODO: RT ERROR if obj is NULL */
return obj;
}
HB_FUNC( QT_QPAGESETUPDIALOG )
{
QPointer< QPageSetupDialog > * pObj = ( QPointer< QPageSetupDialog > * )
hb_gcAllocate( sizeof( QPointer< QPageSetupDialog > ),
&s_gcQPageSetupDialog );
if( hb_pcount() >= 2 )
*pObj = new QPageSetupDialog( hbqt_par_QPrinter( 1 ), hbqt_par_QWidget( 1
) ) ;
else
*pObj = new QPageSetupDialog( hbqt_par_QWidget( 1 ) ) ;
hb_retptrGC( pObj );
}
/*
* virtual int exec ()
*/
HB_FUNC( QT_QPAGESETUPDIALOG_EXEC )
{
QPageSetupDialog * obj = hbqt_par_QPageSetupDialog( 1 );
if( obj )
hb_retni( obj->exec() );
}
[...]
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