Like I already wrote, it has nothing to do with Qt. Qt is a C++ framework, it doesn't do anything special with respect to memory management. So yes, since the OP wrote that the memory was not freed after the application ended then he needs to elaborate on that.

@SGaist ok, is one of my last options (the other is make the post petitions and processing in other thread).

Thanks all. now i got it all clear :)

In general no. QList is not really a linked list (QLinkedList is). It is a sorta vector-list hybrid that allocates chunks of the data as contiguous arrays. How many chunks there are, what is their overhead size, does it hold pointers to elements or optimizes small sized items by holding them in place, what is the alignment overhead - these are all implementation details that affect the size and there's no reliable way to estimate them, or even if you did, they might change in future versions.

Hi and welcome to devnet, If you can reproduce this easily with a minimal compilable example, you should go to the bug report system to see if it's something known. If not please consider opening a new report providing that example and the guidelines to trigger the bug.

How are you deleting your objects? Are you using delete or deleteLater? Seems odd this is happening since any delete on an object will delete all it's children before itself. At least with Qt parenting. If object X isn't a true child of B then that would cause your issue. I.e. if I have: QLabel *label = new QLabel(); QLabel *child = new QLabel(label); delete label; // label should delete child by before it fully deconstructs. Also if you have real code or at the very least a backtrace I could help more.

I will try that also, I will try to pass the container class of the QHash instead of the obj itself.