ptr = (void *)( (char *)ptr - sizeof( struct _PDCLIB_memnode_t ) );
( (struct _PDCLIB_memnode_t *)ptr )->next = NULL;
if ( _PDCLIB_memlist.last != NULL )
ptr = (void *)( (char *)ptr - sizeof( struct _PDCLIB_memnode_t ) );
( (struct _PDCLIB_memnode_t *)ptr )->next = NULL;
if ( _PDCLIB_memlist.last != NULL )