Cleaning up QVector/QContainers?

Dariusz

Hey

When I delete obejct that had QVector<item>/QVector<QMap<item,int>> etc etc assuming the items are not *, do I need to do anything to vectors in ~delete of object holding them or are they automatically cleared/memory released? I'm trying to understand my memory leak :- )

Christian Ehrlicher

@Dariusz said in Cleaning up QVector/QContainers?:

as all will automatically clear up ?

Yes (again)

Christian Ehrlicher

When a container holds objects, the object is deleted when the container is cleared (not Qt-specific)

koahnig

Adding to @Christian-Ehrlicher the object in the container shall have a proper destructor not creating memory leaks itself.

Dariusz

So I though, but as far as I remember... .clear() does not release memory. I have to call something else afterwards to actually release memory. Which make me wonder... if I have to call it in destructor as well ?

Say

class ob{
QVector<int>ints;
QVector<otherOB> otherObs

~ob(){
ints.clear();
ints.squeeze();
otherObs.clear();
otherObs.squeeze();
}

?

Christian Ehrlicher

@Dariusz said in Cleaning up QVector/QContainers?:

indestructor as wel

No, why should you? The container is destroyed automatically in the dtor - c++ basics.

Dariusz

@Christian-Ehrlicher Ok so I don't have to do the ~ob(){} example above in objects at all as all will automatically clear up ?

Christian Ehrlicher

@Dariusz said in Cleaning up QVector/QContainers?:

as all will automatically clear up ?

Yes (again)

kshegunov

@Dariusz said in Cleaning up QVector/QContainers?:

So I though, but as far as I remember... .clear() does not release memory. I have to call something else afterwards to actually release memory. Which make me wonder... if I have to call it in destructor as well ?

clear() releases the memory used by the QVector. If you put pointers in there, then it's going to free the memory the pointers occupied, not the memory the pointers reference - that'd be your job.
In all ways QVector<> is behaving like any other RAII-compliant type.

Calling clear() is not necessary, nor is calling squeeze(), the vector does that automatically when it destructs. Here's a relevant paragraph: http://eel.is/c++draft/stmt.dcl#2

SGaist

Hi,

To delete the content there's qDeleteAll.