[QUOTE=sunil.thaha;35595]Is that an implementation of RAII Idiom ?
I don't have the slightest idea. If it is, then it's unintentional

I found that you have used some undocumented features like the Q_Q and Q_D macros ... and trolltech warns us against the use of these macros. So is it fine to use it or should you create your own Q_WW_D ?
It depends. I use it on my own pointers so it's safe. But you shouldn't use it on pointers Qt provides - I tried