C++ Class Qt 스마트 포인터 (QSharedPointer, QScopedPointer, QPointer) 스마트 포인터는 C++표준 포인터의 모든 기능을 가지고 있으며 자동 가비지 컬렉션 기능을 제공하는 클래스이다. A more complex program sending QSharePointer objects using slots has a similar situation with GDB, that can be reproduced with the previous example. In that case, I think you need to register them. QPointer:: QPointer () Constructs a guarded pointer with value nullptr. One of the important member functions of QSharedPointer is isNull(), which returns true if the pointer is null, and false otherwise. example, this allows calling QObject::deleteLater() on a given object. So, at least, QList and QVector can be filled with it (I am not trying to find high-speed approach). The QSharedPointer is an automatic, shared pointer in C++. C++ (Cpp) QSharedPointer::Count - 2 examples found. Looking for examples of natural languages with affricates but no corresponding fricatives/plosivesMember Function Documentation QSharedPointer < T > QEnableSharedFromThis:: sharedFromThis (). The base class of all event classes. In general, it breaks the concept of having a shared pointer at all. C++ (Cpp) QSharedPointer::GetP2 - 2 examples found. C++ (Cpp) QSharedPointer::GetFormulaRadius - 2 examples found. You can also use a data stream to read/write raw unencoded binary data. QQueue inherits from QList. A class derived from EmployeeData could override that function and return the proper polymorphic type. QSharedPointer 是一个 共享指针 ，它与 QScopedPointer 一样包装了new操作符在堆上分配的动态对象，但它实现的是引用计数型的智能指针 ，也就是说，与QScopedPointer不同的是，QSharedPointer可以被自由地拷贝和赋值，在任意的地方共享它，所以QSharedPointer也可以用作容器. // Create a fresh shared pointer in the scope QSharedPointer<uint8_t> image(new uint8_t[IMG_SIZE]); // the ring buffer can possibly be rewritten on the next usb_read() (if bufferlength = 1) so I copy. When using QSharedPointer to a const object that is derived from QObject the metatyping is trying to register a conversion from const to non-const. That said, your stack trace is really strange:. I am using Qt 5. About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright. 3 as published by the Free Software Foundation. The extracted content is removed automatically once the last reference. The memory corruption can happen if Team object is destroyed before reading its pointer from QMap. to ensure that the pointers being compared are equal. It uses reference counting to track the number of objects sharing the pointer, and. This method may be prefered over using QSharedPointer, since a QExplicitlySharedDataPointer is the same size as a normal pointer. #include "employee. Re: Custom Deleter for QSharedPointer. If this function can determine that the pointer has already been deleted, it returns nullptr. Note that QWeakPointers created this way on arbitrary QObjects usually cannot be promoted to QSharedPointer. std::shared_ptr is a smart pointer that retains shared ownership of an object through a pointer. // Create pointer in constructor. @Yakk: Thanks for that, I've updated my answer to reflect your point. Create an object, and then use the serializer as follows:. The purpose of this class is to lay the T object out next to the reference counts, saving one memory allocation per shared pointer. Example: QPointer < QLabel > label = new QLabel ; label - > setText( "&Status:" );. The QWeakPointer is an automatic weak reference to a pointer in C++. GetInfo(9) GetRemoteId(8) AddChildren(5). There are not so much Qt examples and demos with QSharedPointer because of the general concept for memory management in Qt using parent–child hierarchy of QObject. [/quote] That is a good example to be careful with smart pointers. It's possible that your first thread will execute the if statement, then the other thread will delete your label, and then you will be inside of your if statement and crash. It doesn't take ill luck: calling the destructor of an object that isn't alive is undefined behavior. If a new note is created, its reference is appended to the list: void Traymenu::newNote () { QSharedPointer<Note> note (new Note (this)); m_noteList << note; } For each Note-element, whichs pointers are in m_noteList, I want to get its title and. Previously i had done this: Code: MyObject * object; // Subclass of QObject. Example Before I switched to Qt, I used gtkmm where this was more usual. Be carefull in Qt to combine smart pointers and QObjects parenting. They are often. Yes. Smart pointers facilitate the dynamic memory operations. QSharedPointer는 다른 QSharedPointer 객체가 이를 참조하지 않는 한 범위를 벗어날 때 보유하고 있는 포인터를 삭제합니다. It stores its items in adjacent memory locations and provides fast index-based access. Is this correct? Because the image is so large, I don't want do copies of it and I want it to stay alive until all the. As per the documentation of QSharedPointer, it might be deleting the pointer first time after accessing the element. If I have to share this instance in C++, I'll use QSharedPointer or std::shared_ptr. So QSharedPointer was shelved for 4. A class derived from EmployeeData could override that function and return the. When a QObject is destroyed, it in turn destroys all objects it owns. For instance, the method index returns a QModelIndex that takes a void pointer in the constructor, pointing to one of those. A typical application of this ticker is to make an axis only display integers, by setting the. The following custom cleanup handlers exist: QScopedPointerDeleter - the default, deletes the pointer using delete. As reference the example tested on cross environment using GDB:Qt Base (Core, Gui, Widgets, Network,. [/quote] That is a good example to be careful with smart pointers. These are the ownership "universes" (unless I'm mistaken): 1) Objects created in C++ owned via the QObject parent/child tree. The QSharedPointer is an automatic, shared pointer in C++. It behaves exactly like a normal pointer for normal purposes, including respect for constness. To have that guarantee, use toStrongRef(), which returns a QSharedPointer object. QSharedPointer will delete the pointer it is holding when it goes out of scope, provided no other. Hi, I use QSharedPointer as a smart pointer class, which is very convenient. is not possible perform some atomic operation on two threads with two core processor at the same time. Modifying the data in the container will then affect all. 1 Answer. As long as the shared pointer is in static mutexes map, it will never be deallocated, and the lifetime of mutexes is the lifetime of the program. 1 Answer. I also want to keep track of some of the objects with QSharedPointer instances. As reference the example tested on cross environment using GDB:Member Function Documentation QScopedArrayPointer:: QScopedArrayPointer Constructs a QScopedArrayPointer instance. append(QSharedPointer<MyObject>(new MyObject("second", 2))); Share. h","contentType":"file. h" class Controller { private : QSharedPointer<MyClass. The QSharedPointer is an automatic, shared pointer in C++. Resets this QSharedPointer object to point to t instead. The QSharedPointer internals and the object are allocated in one single memory allocation, which could help reduce memory fragmentation in a long-running application. const QSharedPointer< T > &. C++ (Cpp) QSharedPointer::direction - 6 examples found. QSharedPointer works with forward declarations, so I'd guess you're using it incorrectly; consider giving a minimal example that can be compiled (and more importantly doesn't require us to guess about the types). These are the top rated real world C++ (Cpp) examples of QSharedPointer::isNull extracted from open source projects. . QSharedPointer IF you using a pointer and start giving pointer to other functions and you are passing your pointer all over. QPointer<QHash<QString, QString> > foo ( new QHash<QString, QString> () ); If you really need (smart) pointers to containers, try QSharedPointer, which doesn't require the contained object to be of any specific type. The pointed-to value in the Q_ASSERT will live until the statement finishes. Also, this Q_DECLARE_METATYPE(SharedTestClass) shouldn't be needed. So QSharedPointer was shelved for 4. 1 under Ubuntu 10. Here is a minimal example: #include <QSharedPointer> struct A {}; int main(int argc, char *argv[]) { auto ca = QSharedPointer<const A>::create(); return 0; } Here is one file (not minimal) example but with few working cases, 2 not working and a debug. QDoubleSpinBox: See QSpinBox. [noexcept] const T *QSharedDataPointer:: constData const. As you probably know, at destruction QObject will destroy all their children, this is what we call "QObject memory management". Also, this Q_DECLARE_METATYPE(SharedTestClass) shouldn't be needed. Use this handler for pointers that were allocated with new []. All these news and deletes bothered me when I started in Qt, and I tried to stick to how I did it in gtkmm before. 1) The compiler should be able to perfor RVO or std::move 2) Quite a few classes (especially containers, including QList) use Implicit Sharing i. The temporary instance of the shared pointer allocated on the heap in answer1 will be deallocated by its shared pointer. The requester class should also be in charge of managing the memory of the pointer it created. Study Resources. . 2 Answers Sorted by: 4 You can create a custom connect function: template<class T> bool my_connect (const QSharedPointer<T> &sender, const char. 8. QQueue inherits from QList. As reference the example tested on cross environment using GDB:zar. But you might miss the more convenient BlockingQueue in Java/Python. QExplicitlySharedDataPointer, QScopedPointer, and QSharedPointer. QWeakPointer objects can only be created by assignment from a QSharedPointer. The whole point of this function is to allocate the reference count near the object instance in memory, so you have to let it do the allocation. If a ptr2's template parameter is different from a ptr1's, 1008. This class is used as an index into item models derived from QAbstractItemModel. Only the MyClass object controlled by the QSharedPointer gets deleted. For example, if %m is the largest unit it might become larger than 59 in order to consume larger time values. Example: QPointer < QLabel > label = new QLabel ; label - > setText( "&Status:" );. There are not so much Qt examples and demos with QSharedPointer because of the general concept for memory management in Qt using parent–child hierarchy of QObject. To avoid the cost of thread creation, a thread pool can be used. h","path":"src/corelib/tools/qalgorithms. QSharedPointer is a smart. The following examples can all be compiled and run independently. QSharedPointer is an EXTERNAL to the class and implements a reference counting pointer to a single instance of a class. The QSharedPointer is an automatic, shared pointer in C++. 1 Answer. This blog post is the first in a series that will cover using OpenGL with Qt. The same is for tokencount == 1. 5 Note This class or function is reentrant. This QCPAxisTicker subclass generates ticks with a fixed tick step set with setTickStep. Frequently Used Methods. Test this small example: @ #include <QSharedPointer> class CTest {int INum; public: CTest(): INum ( 0 ) {} int. Your solution is simple. It doesn't do any owning duties. You can rate examples to help us improve the quality of. If this function can determine that the pointer has already been deleted, it returns nullptr . しかし、Qtを使っている場合は、わざわざ自分でMutexの管理をしなくても、スレッドとのデータのやり取りを全て signal/slotでやってしまい、共有データを. Describes how the Qt Remote Objects establishes a direct connection using a static source. You can rate examples to help us improve the quality of examples. But I've not seen it much in use in source code of Examples and Demos. QSharedPointer:: objectCast() works reliably across DLL boundaries, but QSharedPointer:: dynamicCast() and std::dynamic_pointer_cast() don’t. A make_shared () function and a shared pointer class are available in the standard library since C++14, so you could write: #include <memory> //. One problem i have ran into is using signals and slots with the objects that are shared-pointed-to. reset(new int(43)); // correct . 4, but was reborn in 4. See also QSharedPointer and QScopedPointer. This is a very safe way to. Usually one puts this (note that the typedefed name is used as string argument): qRegisterMetaType< QSharedPointer >("SharedTestClass"); in main() not as a global variable. QPointer 、 QSharedPointer 、 QWeakPointerクラスに関するQtのドキュメントを読みました。それは言う： QPointerは、Qtオブジェクトへの保護されたポインタを提供し、参照されたオブジェクトが破棄され、 "ぶら下がっているポインタ"が生成されないときに自動的に0に設定される点を除いて、通常のC. QSharedPointer holds a shared pointer by means of an external reference count (i. There are not so much Qt examples and demos with QSharedPointer because of the general concept for memory management in Qt using parent–child hierarchy of QObject. , a reference counter placed outside the object). In short - an atomic operation is one that is so "small" (hence the name) that it cannot be interrupted (for example by another thread) and therefore is thread-safe. Also, this Q_DECLARE_METATYPE(SharedTestClass) shouldn't be needed. See also QSharedPointer and QScopedPointer. These are the top rated real world C++ (Cpp) examples of QSharedPointer::node extracted from open source projects. 04 and in my application I need to use QSharedPointer together with the appropriate dynamic_cast (object_cast) conversions at runtime. Code that makes use of delete are candidates for QScopedPointer usage (and if not, possibly another type of smart pointer such as QSharedPointer). My app uses QSharedPointers throughout the C++ API, where instead of returning an object, it usually returns a smart pointer to it and every class has an accompanying typedef for convenience. These are the top rated real world C++ (Cpp) examples of QSharedPointer::getShapes extracted from open source projects. 1. Previously i had done this: Qt Code: Switch view. If somehow the object/container survives so does the smart pointer and the allocated memory. In the example above, the template specialization for the clone() function calls the EmployeeData::clone() virtual function. LMNode::setParent(const QSharedPointer<LMNode>& parent) { this->parent = parent; } const QSharedPointer<LMNode>& LMNode::getParent() { return this->parent; } Sure, in the second version i avoid the increment of the reference counter and the changing of the QSharedPointer object. As reference the example tested on cross environment using GDB:I'm trying to use QSharedPointer to define an object that will be created in a thread that will emit a signal to another thread. class SomeClass { SomeClassP getInstance () { return SomeClassP (new SomeClass ()); } } typedef. The code below won't leak memory and doesn't invoke any undefined behavior. This can be used to retrieve QMetaMethod and QMetaProperty and use them on a pointer of this type for example, as given by QVariant::data(). 9. QSharedPointer will delete the pointer it is holding when it goes out of scope, provided no other QSharedPointer objects are referencing it. Passing data through threads is a common task in multi-thread programming. The code the compiler generates for QScopedPointer is the same as when writing it manually. Like its name indicates, the pointer value is shared among all instances of QSharedPointer and QWeakPointer. behaves exactly like a normal pointer for normal purposes, including respect for constness. These are the top rated real world C++ (Cpp) examples of QSharedPointer::StopTimer extracted from open source projects. docx from EEET 1026 at University of South Australia. BTW: I know that std::unique_ptr does not do the same as QSharedPointer, because the latter does reference counting. See also QSharedPointer and QPointer. If you refactor your code so that all new operator are in lines like these, all your problems will be solved. See Customizing QDockWidget for an example. That said, your stack trace is really strange:. 5k 15 97 178. It behaves exactly like a normal pointer for normal purposes, including respect for constness. Frequently Used Methods. The item object can be destroyed by QSharedPointer destructor, so QChache will have invalid pointer. This function was introduced in Qt 4. QSharedPointer<QMap<int, bool>> mpsptr = QSharedPointer<QMap<int, bool>>::create (QMap<int, bool> { {1, false}}); Ok, I found an answer that works for me. Detailed Description. It. In a related question: Waiting slots to be executed before quitting. referencing it. Each QCPAxis has an internal QCPAxisTicker (or a subclass) in order to generate tick positions and tick labels for the current axis range. Using lambdas as slots is straightforward (for example for an event from a QSpinbox): connect (spinboxObject, &QSpinBox::editingFinished, this, [this] () {<do something>}); But this works only if the signal is not overloaded (that means there are several signals with the same name but different arguments). The Qt documentation suggests that using the QSharedDataPointer with a visible implementation of its inferior is not typical. Creating and destroying threads frequently can be expensive. QSharedPointer < T > QEnableSharedFromThis:: sharedFromThis If this (that is, the subclass instance invoking this method) is being managed by a QSharedPointer, returns a shared pointer instance pointing to this; otherwise returns a null QSharedPointer. The QSharedPointer is an automatic, shared pointer in C++. QSharedPointer is a smart pointer class in Qt that provides shared ownership of objects. 4. Children are typically added to a QObject *parent from their constructor with new QObject(parent);. You can rate examples to help us improve the quality of examples. The QPointer class is a template class that provides guarded pointers to QObject. I am using Qt 5. A class derived from EmployeeData could override that function and return the proper polymorphic type. C++ (Cpp) QSharedPointer::GetCenter - 3 examples found. QSharedPointer:: objectCast() works reliably across DLL boundaries, but QSharedPointer:: dynamicCast() and std::dynamic_pointer_cast() don’t. Define the EmployeeData class derived from. Their main advantage is reducing memory leaks and bugs due to poor memory management. It never will deallocate any storage owned by QObject. Examples and Tutorials Supported Platforms What's new in Qt 6 Qt Licensing Overviews Development Tools User Interfaces Core Internals. QSharedPointer:: QSharedPointer (const QWeakPointer < T > &other) Creates a QSharedPointer by promoting the weak reference other to strong reference and sharing. QSharedPointer<MyClass> mc (new MyClass ()); mc->testSharedThis (); QScopedPointer's second template parameter can be used for custom cleanup handlers. The problem is that this code is creating a QSharedPointer from a raw pointer, which implies ownership of the object pointed to. I've been playing with null d pointers for the past 3 years and I've never made it work and I wasn't even trying to keep BC. The source can be found in the examples directory: examples/tutorials/threads/ Example 1: Using the Thread Pool. . qRegisterMetaType< QSharedPointer<TestClass> >("SharedTestClass"); in main() not as a global variable. Since the replicas have the same properties, signals, and slots as were. 1 under Ubuntu 10. Hi all. The interface: Model. The QSharedPointer class holds a strong reference to a shared pointer The QSharedPointer is an automatic, shared pointer in C++. The examples on Wikipedia makes no sense to me. detach from the underlying data. ) summary refs log tree commit diff statsQMetaType::construct (), QMetaType::sizeOf (), and QMetaType::alignOf. qRegisterMetaType is required for the queued connection. [/quote] There are not so much Qt examples and demos with QSharedPointer because of the general con. Modifying the data in the container will then affect all curves that share the container. Before drawing you would create a local QSharedPointer<MyClass> in the drawing function and check if it is valid. C++ (Cpp) QSharedPointer Examples. This example creates a QSharedPointer object that references an int value. QSharedPointer:: objectCast() works reliably across DLL boundaries, but QSharedPointer:: dynamicCast() and std::dynamic_pointer_cast() don’t. here is a. You can use smart pointers to hold you item in your QList, for example QSharedPointer<MyCustomObj>. Returns a list of child objects. There are several ways to avoid the problem in this particular example I can think of: change Test destructor to expect null m, write template template<typename T> inline T no_move (T&& tmp) {return tmp;}, explicitly create temporary Test object in assign, add getter for m and call it to force copying m (advised by Jarod42 ); MS Visual Studio. MyObject * object; // Subclass of QObject. Example: QPointer < QLabel > label = new QLabel ; label - > setText( "&Status:" );. 4, but was reborn in 4. It is usually best to use a mutex with a QMutexLocker since this makes it easy to ensure that locking and unlocking are performed consistently. Good day QT'ers, wondering if there's a better way to remove a QSharedPointer from a QList loaded with them. For example: class ScriptInterface :publicQObject { Q_OBJECT //. Args> QSharedPointer<T> QSharedPointer<T>::create(Args &&. . See QWeakPointer::toStrongRef() for an example. The QSharedPointer is an automatic, shared pointer in C++. To complicate things, debugging reports had absolutely random pattern as well. 8. C++ (Cpp) QSharedPointer::direction - 6 examples found. 4. The QSharedPointer is an automatic, shared pointer in C++. But I've not seen it much in use in source code of Examples and Demos. Args> QSharedPointer<T> QSharedPointer<T>::create(Args &&. QTest. These are the top rated real world C++ (Cpp) examples of QSharedPointer::isSelected extracted from open source projects. Qt 6 youtube videos by Bry. QSharedPointer guarantees that the object isn't deleted, so if you obtain a non-null object, you may use the pointer. When removeData() returns, any further attempts to reference the sender is undefined behavior. exec () (which represents the main event loop of Qt App) has already. Show the scaled images in a grid layout. Both serialization and desertialization are rather simple. I worked around this by extracting a raw pointer from the QSharedPointer: The template parameter is the type T of the class which QSharedPointer tracks. In all other cases an invalid. Code that makes use of delete are candidates for QScopedPointer usage (and if not, possibly another type of smart pointer such as QSharedPointer). combination used to implement implicit sharing, both in Qt itself and. The pointer ptr becomes managed by this QSharedPointer and must not be passed to another QSharedPointer object or deleted. If we have smart pointers in Qt, why old C type pointers are preferred ? Reply Quote 0. For example, using data() for QObject::connect() would be save, but. Example: QPointer < QLabel > label = new QLabel ; label - > setText( "&Status:" );. Improve this answer. If you refactor your code so that all new operator are in lines like these, all your problems will be solved. io First of all, could anyone please give me an example where you would ACTUALLY use shared pointers. publicslots: void slotCalledByScript(Y *managedBySharedPointer) { QSharedPointer<Y> yPtr =. 1010. With new QProcess (this);, you made the new QProcess object owned by this instance of MainWindow. args) overload since 5. The QCPGraphDataContainer is an abstract data container of QCPGraphData object, one of which will be created for each data point that we parse. The index is used by item views, delegates, and selection models to locate an item in the model. The example will output 1, 2, 3 in that order. QSharedPointer:: objectCast() works reliably across DLL boundaries, but QSharedPointer:: dynamicCast() and std::dynamic_pointer_cast() don’t. @xylosper said in How to manage QObject instance which is shared among lots of C++/QML places:. Make a typedef for QSharedPointer<UserDataType>, and use both Q_DECLARE_METATYPE as well as qRegisterMetaType () to register it for use. New QModelIndex objects are created by the model using the QAbstractItemModel::createIndex () function. @Yakk: Thanks for that, I've updated my answer to reflect your point. Stack Overflow Public questions & answers; Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Talent Build your employer brand ; Advertising Reach developers & technologists worldwide; Labs The future of collective knowledge sharing; About the companyConsider a simple example that creates two instances of the implicitly shared Employee class. If you type is base on QObject, you have to take care to avoid double free if they have a parent. Also, this Q_DECLARE_METATYPE(SharedTestClass) shouldn't be needed. These are the top rated real world C++ (Cpp) examples of QSharedPointer::update extracted from open source projects. I want to prevent something as this: Qt Code: Switch view. For example, you can use isEmpty() to test whether the queue is empty, and you can traverse a QQueue using QList's iterator classes (for example, QListIterator). QSharedPointer will delete the pointer it is holding when it goes out of scope, provided no other QSharedPointer objects are referencing it. This is the pattern that the automatic data collector will look for and parse. 1009. These are the top rated real world C++ (Cpp) examples of QSharedPointer::GetSubscriptionTypeStr extracted from open source projects. A guarded pointer, QPointer<T>, behaves like a normal C++ pointer T *, except that it is automatically set to 0 when the referenced object is destroyed (unlike normal C++ pointers, which become "dangling pointers" in such cases). h","contentType":"file. Not sure I got you there. See QWeakPointer::toStrongRef () for an example. Extracts a directory from resources to disk. > Regards, > > Alex > > > Rudenko Eugene a écrit : >> Hello. It behaves exactly like a normal pointer for normal purposes, including respect for constness. So a conclusion would be: watch out for run-away. 212: 213: This class is never instantiated directly: the constructors and: 214 In the example above, the template specialization for the clone() function calls the EmployeeData::clone() virtual function. referencing it. qRegisterMetaType< QSharedPointer<TestClass> >("SharedTestClass"); in main() not as a global variable. Maybe I have bad expressed. data (); } When you delete the pointed-to object, data () will be null. [quote author="situ117" date="1304279927"] I was reading about QSharedPointer in Qt. It. You can rate examples to help us improve the quality of. One example may be the case where you store lots of pointers to objects in a container class. Actually, it does so in examples setting custom deleter to Object::deleteLater . In many cases, that UB may be innocuous, but it is UB regardless. The interface is straight forward, just the forward declaration of the private class and the. When the last associated QSharedPointer goes out of scope, the object will be deleted. MyObject * obj = sharedPointerToObject. If used in this way, you can pass around these references and use them like pointers, and. I would still recommend you to use 2/3, as. out of scope, provided no other QSharedPointer objects are. For the sake of the example: Don't return a pointer to QList<>, return the QList<> itself. Most of the time it is not a good idea to use raw pointers (in modern C++). Examples at hotexamples. C++ (Cpp) QSharedPointer::getReferencedBlockId - 4 examples found. Otherwise, the object deletes itself after emitting the signal. QSharedPointer guarantees that the object isn't deleted, so if you obtain a non-null object, you may use the pointer. It works like variables in Java and CPython, or like std::shared_ptr. For QSharedPointer . You can inherit this class when you need to create a QSharedPointer from any instance of a class; for instance, from within the object itself. For example "sample: 45 2048". When removeData() returns, any further attempts to reference the sender is undefined behavior. Share. C++ (Cpp) QSharedPointer Examples. The object is destroyed and its memory deallocated when either of the following happens: the last remaining shared_ptr owning the object is destroyed; ; the last remaining shared_ptr. 详细描述. ) summary refs log tree commit diff statsIn summary, you would need to go through the constructor and operator= as follows: Qsharedfoo = QSharedPointer<T> (rawfoo); // operator= () overload. It provides a safer and easier way to manage dynamic memory allocation and deallocation by automatically managing the reference counting of a shared object. Depending on your use case that might be a better. The QSharedPointer is an automatic, shared pointer in C++. If this metatype represents an enumeration, this method returns a metatype of a numeric class of the same signedness and size as the enums underlying type. There are not so much Qt examples and demos with QSharedPointer because of the general concept for memory management in Qt using parent–child hierarchy of QObject. Good Morning everyone, I am using QSharedPointer with my classes derived from QObject. [noexcept] const T *QSharedDataPointer:: constData const. The QSharedPointer class holds a strong reference to a shared pointer More. Example. It does not manage the object it points to. Maybe you want to collect for example "time:", "accuracy:" or "position:" samples for your particular use case. A simple code that could reproduce the issue. QSharedPointer.