Pass QScopedPointer to function

Question

How can I pass a QScopedPointer object to another function like that:

bool addChild(QScopedPointer<TreeNodeInterface> content){
   TreeNode* node = new TreeNode(content);
}

TreeNode:

TreeNode::TreeNode(QScopedPointer<TreeNodeInterface> content)
{
    mContent.reset(content.take());
}

I get: error: 'QScopedPointer::QScopedPointer(const QScopedPointer&) [with T = TreeNodeInterface; Cleanup = QScopedPointerDeleter]' is private

How can I solve it? Thanks!

Answer 1

You can do it by accepting a reference to the pointer - that way you can swap the null local pointer with the one that was passed to you:

#include <QScopedPointer>
#include <QDebug>

class T {
   Q_DISABLE_COPY(T)
public:
   T() { qDebug() << "Constructed" << this; }
   ~T() { qDebug() << "Destructed" << this; }
   void act() { qDebug() << "Acting on" << this; }
};

void foo(QScopedPointer<T> & p)
{
   using std::swap;
   QScopedPointer<T> local;
   swap(local, p);
   local->act();
}

int main()
{
   QScopedPointer<T> p(new T);
   foo(p);
   qDebug() << "foo has returned";
   return 0;
}

Output:

Constructed 0x7ff5e9c00220 
Acting on 0x7ff5e9c00220 
Destructed 0x7ff5e9c00220 
foo has returned