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// Copyright (C) 2018 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
//! [0]
class Y: public QEnableSharedFromThis<Y>
{
public:
QSharedPointer<Y> f()
{
return sharedFromThis();
}
};
int main()
{
QSharedPointer<Y> p(new Y());
QSharedPointer<Y> y = p->f();
Q_ASSERT(p == y); // p and q must share ownership
}
//! [0]
//! [1]
class ScriptInterface : public QObject
{
Q_OBJECT
// ...
public slots:
void slotCalledByScript(Y *managedBySharedPointer)
{
QSharedPointer<Y> yPtr = managedBySharedPointer->sharedFromThis();
// Some other code unrelated to scripts that expects a QSharedPointer<Y> ...
}
};
//! [1]
//! [2]
static void doDeleteLater(MyObject *obj)
{
obj->deleteLater();
}
void otherFunction()
{
QSharedPointer<MyObject> obj =
QSharedPointer<MyObject>(new MyObject, doDeleteLater);
// continue using obj
obj.clear(); // calls obj->deleteLater();
}
//! [2]
//! [3]
QSharedPointer<MyObject> obj =
QSharedPointer<MyObject>(new MyObject, &QObject::deleteLater);
//! [3]
//! [4]
if (sharedptr) { ... }
//! [4]
//! [5]
if (!sharedptr) { ... }
//! [5]
//! [6]
QSharedPointer<T> other(t); this->swap(other);
//! [6]
//! [7]
QSharedPointer<T> other(t, deleter); this->swap(other);
//! [7]
//! [8]
if (weakref) { ... }
//! [8]
//! [9]
if (!weakref) { ... }
//! [9]
//! [10]
qDebug("Tracking %p", weakref.data());
//! [10]
//! [11]
// this pointer cannot be used in another thread
// so other threads cannot delete it
QWeakPointer<int> weakref = obtainReference();
Object *obj = weakref.data();
if (obj) {
// if the pointer wasn't deleted yet, we know it can't get
// deleted by our own code here nor the functions we call
otherFunction(obj);
}
//! [11]
//! [12]
QWeakPointer<int> weakref;
// ...
QSharedPointer<int> strong = weakref.toStrongRef();
if (strong)
qDebug() << "The value is:" << *strong;
else
qDebug() << "The value has already been deleted";
//! [12]
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