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c++qtobjectobject-lifetime

Lifetime of Qt Objects

What are the lifetimes of Qt Objects?

Such as:

QTcpSocket *socket=new QTcpSocket();

When socket will be destroyed? Should I use 

delete socket;

Is there any difference with:

QTcpSocket socket;

I couldn't find deep infromation about this, any comment or link is welcomed.

Solution

  • Qt uses parent-child relationships to manage memory. If you provide the QTcpSocket object with a parent when you create it, the parent will take care of cleaning it up. The parent can be, for example, the GUI window that uses the socket. Once the window dies (i.e. is closed) the socket dies.

    You can do without the parent but then indeed you have to delete the object manually.

    Personally I recommend sticking to idiomatic Qt and using linking all objects into parent-child trees.