Hi Mindaugas,
I expect pointer not to be collected, because it "lives" in variable h.
No. Not always. See below ...
What's wrong with my code?
Read below ...
PROC main()
LOCAL h
h := myfunc( h )
You call h := myfunc( h ). h is empty so hb_gcAlloc()
is called in myfunc() and the result is stored in h.
Note that the result has got "an assinged garbage"
func hb_fctx_destructor() to it.
debug( "1" )
h := myfunc( h )
You call h := myfunc( h ). h is not empty so hb_gcAlloc()
is not called. But a new item is returned and stored in h.
And now the old item stored in h previously, does not belong
to any item and it is freed by GC. However a new item is not
a "garbage" item, because no hb_gcAlloc() was called for it,
so it will not be touched by GC in a future (no "garbage"
func will be called for this item).
debug( "2" )
h := myfunc( h )
debug( "3" )
RETURN
#pragma begindump
#include "hbapi.h"
static HB_GARBAGE_FUNC( hb_fctx_destructor )
{
(void) Cargo;
fprintf( stdout, "destructor\n" );
}
HB_FUNC( DEBUG )
{
fprintf( stdout, hb_parc( 1 ) );
fprintf( stdout, "\n" );
}
HB_FUNC( MYFUNC )
{
void* ptr = hb_parptrGC( hb_fctx_destructor, 1 );
if( ! ptr )
{
ptr = hb_gcAlloc( 4, hb_fctx_destructor );
}
hb_retptrGC( ptr );
}
#pragma enddump
--
Marek
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