The Windows registry and INI files use case-insensitive keys, whereas the CFPreferences API on macOS and iOS uses case. For the moment, moc will extract and record all tags, but it will not handle any of them specially. goocreations 12 Mar 2013, 07:22. Any class or struct that has a public default constructor, a public copy constructor, and a public destructor can be registered. ) QObject::connect: Cannot queue arguments of type 'QVector<int>' (Make sure 'QVector<int>' is registered using qRegisterMetaType(). ) QObject: Cannot create children for a parent that is in a different thread. Every second this 2d array is changed by a thread (representing the passage of time) and then this thread emits a signal telling the main GUI to update based on the new game board. h. QObject::connect: Cannot queue arguments of type 'QVector<QVector<int> >'. QPainter supports drawing lines, polygons, vector paths, images, and text. qRegisterMetaType () is called to register the TYPE and generate a TYPE ID. template <typename T> struct QMetaTypeId<Container<T>>. You don't have to register your data type via qRegisterMetaType, and when you send your data as a reference it is not copied. October 21, 2020 by Fabian Kosmale | Comments As you might know, Qt has a metatype system which provides run-time dynamic information about types. ) I register my class like this after it's declaration: Q_DECLARE_METATYPE(taservices::ProcessHandle*); I also added this static method which I call from constructor: QObject::connect: Cannot queue arguments of type 'QProcess::ProcessError' (Make sure 'QProcess::ProcessError' is registered using qRegisterMetaType(). Where are you getting this from? qRegisterMetaType is not a member function of QSettings or any other class. Asking for help, clarification, or responding to other answers. In practice, both the Q_DECLARE_METATYPE() macro and the qRegisterMetaType() template function can be used to register custom types, but qRegisterMetaType() is only required if you need to perform. 我们知道类中的成员函数并不一定会被调用(即，该宏并不确保类型被注册到MetaType)。 通过qRegisterMetaType可以确保类型被注册; 两个qRegisterMetaType 的联系如果还希望使用这种类型的引用，可同样要注册：qRegisterMetaType<TextAndNumber>("TextAndNumber&"); 版权声明：本文为wangzhiqian7hao原创文章，遵循 CC 4. QObject::connect: Cannot queue arguments of type 'QVector<int>' (Make sure 'QVector<int>' is registered using qRegisterMetaType(). childKeys();@J. SIGNAL(ueSignalTaskFinished(UePosCommProtocolArch::UeCommand&, // reference QByteArray&)), //dittoCustom types registered using qRegisterMetaType() that have operators for streaming to and from a QDataStream can be stored using QSettings. Following this logic, the following code may not work: connect (senderObject. The same plugin may be loaded multiple times during the application's lifetime. Registration is not required for most operations; it’s only required for operations that attempt to resolve a type name in string form back to a QMetaType object or the type’s ID. new children are appended at. If you want to pass IBase * between different threads, you need to register class with qRegisterMetaType<IBase *> () call; It is bad practice to pass pointers throught singals, because it is hard to control lifetime of passed objects. My original script use this : from PyQt5. Thanks for contributing an answer to Stack Overflow! Please be sure to answer the question. Steps to reproduce. (Make sure 'MyStruct' is registered using qRegisterMetaType (). (Make sure 'QDomDocument' is registered using qRegisterMetaType(). What worries me is that. QChildEvent. 4. And then Python crashes. Yet, the first line is invisible and this line becomes visible only if we click on it! Very weird! QObject::connect: Cannot queue arguments of type 'QTextCursor'. When data values are exchanged between QML and C++, they are converted by the QML engine to have the correct data types as appropriate for use in QML or C++. The default value is Data8, i. ) The text was updated successfully, but these errors were encountered: QObject::connect: Cannot queue arguments of type 'object' (Make sure 'object is registered using qRegisterMetaType(). 我们知道类中的成员函数并不一定会被调用 (即，该宏并不确保类型被注册到MetaType)。. So you can call it from your constructor. clicked. TEST_VIEW4 contains a QML folder with a specific folder for this QML code. ). mycompany. You need to create your own factory that will register functors that will call qRegisterMetaType in runtime. qRegisterMetaType <Card::Orientation> ( "Card::Orientation" ); QSignalSpy. An "ugly solution" would be to hack the fairly simple QSignalSpy code in order to handle the reference passed arguments. The habit of passing shared_ptr by ref should not be followed in lambdas. Any class or struct that has a public default. To call qRegisterMetaType (), you still need to use Q_DECLARE_METATYPE (). Improve this answer. Be very careful as cv::Mat is not implicitly shared, it is just shared (i. qRe gisterMetaType 的函数原型为： ```c++ template < type name T> int. void QVariant:: clear (). This also makes the type available for queued signal-slot communication as long as you call it before you make the first connection that uses the type. ) QObject::connect: Cannot queue arguments of type 'QVector<int>'. Qt. 步骤： (以自定义MyDataType类型为例）. QSignalSpy can connect to any signal of any object and records its emission. on top of main. Maybe qRegisterMetaType is what you missed. When a signal is emitted, the corresponding signal handler is invoked. 15. Qt is complaining about QObject::connect: Cannot queue arguments of type 'QTextCursor' (Make sure 'QTextCursor' is registered using qRegisterMetaType(). . adam-iris added a commit that referenced this issue Oct 11, 2017. With Q_DECLARE_METATYPE and without qRegisterMetaType: No warning, slot is called With Q_DECLARE_METATYPE and with qRegisterMetaType: No warning, slot is called. Obviously then you would not do registerComparator (). QML has a signal and handler mechanism, where the signal is the event and the signal is responded to through a signal handler. QObject: Cannot create children for a parent that is in a different thread. #pragma once #include <QObject> class MyClass : public QObject { Q_OBJECT public: static void initQML (); MyClass (); MyClass (const MyClass &myClass. First of all, shared_ptr needs an (external, in general) reference counter to be allocated. Edit: from @altaf comments : To clarify, the root of the problem was cause by qRegisterMetaType<Data> ("Data"); in my main. (Make sure 'QVector<int>' is registered using qRegisterMetaType(). connect(self. PySide2. (Make sure 'QVector<int>' is. That's probably there, as qRegisterMetaType () wouldn't compile otherwise. QSignalSpy itself is a list of QVariant lists. – pmf Feb 7, 2019 at 16:35 QObject::connect: Cannot queue arguments of type 'QTextCursor' (Make sure 'QTextCursor' is registered using qRegisterMetaType(). As you have already found out, you must use Q_DECLARE_METATYPE to make the type known to Qt. The only changes were made to initArgs and appendArgs functions. QObject::connect: Cannot queue arguments of type 'QVector<int>' (Make sure 'QVector<int>' is registered using qRegisterMetaType(). The Qt GUI module contains classes for 2D graphics, imaging, fonts, and advanced typography. Also you may need to use qRegisterMetaType function. The. 子线程中：QMap<QString, QString> testMap; emit testSignal(testMap);Call qRegisterMetaType() to make type available to non-template based functions, such as the queued signal and slot connections. The following code allocates and destructs an instance of MyClass:The Q_DECLARE_METATYPE() macro and qRegisterMetaType() function documentation contain more detailed information about their uses and limitations. tab) self. QtGui. 9k 13 13 gold badges 106 106 silver badges 138 138 bronze badges. An item selection can be constructed and initialized. The correct syntax is Q_DECLARE_METATYPE (std::string) without the ;. 1 Reply Last reply . Type names can be registered with QMetaType by using either qRegisterMetaType () or registerType (). I explicitly don't want to update it on every change to one of the quantities, so they don't. I'll take your word on that, because on my rig fixing the return type of area() and providing the empty template parameter list for the specialization leaves only get() failing to compile, and as near as I can tell it may be because of the order this was pasted into the question. There is a name index for fast lookup of the meta type id. You'll need Q_DECLARE_METATYPE () if you want to store your type within a QVariant and you will additionally need qRegisterMetaType<> () if you want to dynamically create and destroy objects of that type at runtime, mostly for queued signal and slots connections or the QObject property system. Oct 17, 2014 at 14:12. Provide details and share your research! But avoid. Data Type Conversion Between QML and C++. Any class or struct that has a public default constructor, a public copy constructor and a public destructor. Q_ASSERT_X (normalizedTypeName == QMetaObject::normalizedType (normalizedTypeName. Any class or struct that has a public default constructor, a public copy constructor, and a public destructor can be registered. 5 and Qt Version 5. bool QMetaProperty:: writeOnGadget ( void * gadget, const QVariant & value) const. Adding a Q_DECLARE_METATYPE() makes the type known to all template based functions, including QVariant. an int and a std::string. QtCore. bool QAbstractItemModel:: insertColumn ( int column, const QModelIndex & parent = QModelIndex ()) Inserts a single column before the given column in the child items of the parent specified. Section and Key Syntax# Setting keys can contain any Unicode characters. iv. (Make sure 'QQuickChangeSet' is registered using qRegisterMetaType (). See also. Any QQmlContext's created on this engine will be invalidated, but not destroyed (unless they are parented to the. 1 Answer. QObject is the heart of the Qt Object Model . The physical memory sizes returned include the memory from all nodes. You could wrap the used functions and classes into custom widgets or plain py-files and in your main frame class only import those custom widgets. 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. Although I have not made clear the specific meaning, at least it can work well. 2、使用 qRegisterMetaType，将对象注册为元类型 使用qRegisterMetaType对自. The factory must be set before executing the engine. The Rep lica C ompiler (repc) generates QObject header files based on an API definition file. ) The image I am trying to pass is a cv::Mat which I converted to a QImage which I afterwards converted to a QString. I made some experiments with moving . It provides functions for creating and manipulating selections, and selecting a range of items from a model. )@. Q_DECLARE_METATYPE与qRegisterMetaType学习. ) I read on some forum, that this may be caused by calling qt-functions from another Thread, and that using signals & slots instead of plain function calling may fix the issue, but i have tried signals aswell, and i. . hEvaluating Scripts. Please visit robotics. qmlRegisterType makes the QObject (MyClass) class accessible in QML (Q_PROPERTY, Q_ENUM, Q_SIGNAL, Q_SLOT, Q_INVOKABLE, etc. bool QLocalSocket. g. These are syntactically atrocious, but that’s templates for you. ", which suggests it is only for classes and structs. 3. Call qRegisterMetaType<std::string> (); in the initialization of your code. This member is allocated and filled with data from a qt slot like so: int channel_count =. 我们知道类中的成员函数并不一定会被调用(即，该宏并不确保类型被注册到MetaType)。 通过qRegisterMetaType可以确保类型被注册; 两个qRegisterMetaType 的联系In part II of our Qt for Beginners Summer Webinar Series we will explore how Qt is so much more than just a GUI toolkit. Share. If you need a socket, you have two options: Instantiate QTcpSocket or QUdpSocket. Detailed Description#. (Make sure 'QVector' is registered using qRegisterMetaType(). One or many threads can block waiting for a QWaitCondition to set a condition with wakeOne() or wakeAll(). However, I cannot figure out how to verify that the included parameter is FACE_UP or FACE_DOWN. 它的作用是将自定义的数据类型转换为Qt元对象系统中的类型，使得这些类型可以在不同线程之间进行信号槽的传递。. Then the TYPE ID is saved in local static vairable metatype_id. no unexpected garbage. 2、在类型定义完成后，加入声明：Q_DECLARE_METATYPE (MyDataType); 3、在main ()函数中. Make sure 'QTextCursor' is registered using qRegisterMetaType(). qRegisterMetaType you'll need if creating objects by class name dynamically, and it seems for queued connections, generally you won't. qRegisterMetaType 将某类型注册中 MetaType 系统中. I intially installed a later version of Qt but then reverted back to Version 5. In the order provided above it won't compile for me unless get() is specifically. If I register QVector I can't dissconnect this signal and the signal is emited. You can call this function in a subclass of QAbstractSocket to change the return value of the localPort () function after a connection has been established. You need to (or at least this is how it works for me) create a signal that will be emitted every iteration of the for loop in your thread. Specifically, the function have to be called before using the struct in a queued signal/slot connection or before. It just allows you to queue types that. When data values are exchanged between QML and C++, they are converted by the QML engine to have the correct data types as appropriate for use in QML or C++. The difference between Qt::QueuedConnection and Qt::AutoConnection is due to a difference in the. qRegisterMetaType<QSqlDatabase>("QSqlDatabase"); Just changing the signal to this form: void dbConnected(QSqlDatabase *db); And, in the slot side I'll use something like this: void onDBConnected(QSqlDatabase * const db); I'm concerned with the usage of db (as in the beginning I've made the reference const), so I make it const here (in the slot. rep file extension, short for Replica. ) QObject::connect: Cannot queue arguments of type 'QModelIndex' (Make sure 'QModelIndex' is registed using qRegisterMetaType(). a copy of a cv::Mat object will point to the same data as the copied from item). Follow answered Jan 29, 2016 at 11:01. 用qRegisterMetaType对自定义的类型进行注册，就是为了告诉Qt如何去做这些事情。. Doc states:. More frustrating is I've found PySide documentation alluding to the use of qRegisterMetaType, but I can't find out where to call it from. I'm using Qt 5. said, try to directly pass shared_ptr with your signal/slots. This maybe is not the nicest solution, but it works just fine: Add a property to the wizardpage which contains the QListView and let it return the pointer to the selectionmodel. (Make sure 'QVector<QVector<int> >' is registered using qRegisterMetaType (). If a field is empty, don't include it in the result. (Parent is QTcpSocket (0x24a6ce8), parent's thread is ServiceSlots. e. qRegisterMetaType<QVector<int> > ("QVector<int>"); Once you make this call, you should be able to emit the QVector type over queued connections. すべてのソケットで読み書きができるようになりました。しかし、これらすべてのインスタンスをオーケストレーションするためのサーバがまだ必要です。4. the connect () call returns true, but when the signal is emitted, Qt outputs this: QObject::connect: Cannot queue arguments of type 'uint64'. complains that the metatype isn't registered. Nejat Nejat. If you need a socket, you have two options: Instantiate QTcpSocket or QUdpSocket. Got a similar example working without explicitly calling qRegisterMetaType() just by removing the semicolon from the line Q_DECLARE_METATYPE(StateMachine::state) – user666412. 11. QObject::connect: Cannot queue arguments of type 'QAbstractSocket::SocketState' (Make sure 'QAbstractSocket::SocketState' is registered using qRegisterMetaType(). Any class or struct that has a public constructor, a public copy constructor, and a public destructor can be registered. receiver. You can use the tags to annotate your methods. Through two classes, QObject and QVariant, Qt brings us introspection, makes it easier to manage memory in C++ and makes it easier to decouple classes. When these files are processed by repc, repc generates both Source and Replica header files. It will look for the signature of methods using string matching. The QObject documentation states that the copy-constructor should be private, but the QMetaType documentation states that a type should have a public default constructor, a public copy constructor, and a public destructor. Improve this answer. So using qRegisterMetaType () you will just trade Q_ENUM () for Q_DECLARE_METATYPE (). Call qRegisterMetaType() to make types available to non-template based functions, such as the queued signal and slot connections. 1,609 4 22 34. program exits if. Instead, we should pass weak_ptr to a shared_ptr. qRegisterMetatype should be enough. cpp 0: 142: 143: If c MyStruct is in a namespace, the Q_DECLARE_METATYPE() macro: 144: has to be outside the namespace: 145: 146adam-iris modified the milestone: Beta Release Aug 25, 2017. (Make sure 'QModelIndex' is registed using qRegisterMetaType(). 14. Although you can just create QBluetoothDeviceInfo objects on your own and fill them with data, the easier way is to use the QBluetoothDeviceDiscoveryAgent to start an automated search for visible Bluetooth devices within the connectable range. – pmf Feb 7, 2019 at 16:35QObject::connect: Cannot queue arguments of type 'QTextCursor' (Make sure 'QTextCursor' is registered using qRegisterMetaType(). I can confirm the observed behaviour. QtCore. To register VideoMeta you need to call qRegisterMetaType<VideoMeta>(). Just installing it did not work for me. This requires the exchanged data to be of a type that is recognizable by the engine. qRegisterMetaType<Subclass> ("Subclass") also doesn't work. It associates a type name to a type so that it can be created and destructed dynamically at run-time. ", which suggests it is only for classes and structs. Someone may be able to correct me here, but I don't think you should be needing to register the type int&. From the docs: int qRegisterMetaType ( const char * typeName ) Registers the type name typeName to the type T. Any class or struct that has a public default constructor, a public copy constructor and a public destructor can be registered in QMetaType. multithreaded software and I am getting the warning says: (Make sure. ui. int QMetaObject:: indexOfSignal (const char * signal) const. See QMetaType docs for more information. QObject::connect: Cannot queue arguments of type 'my_enum' (Make sure 'my_enum' is registered using qRegisterMetaType(). com to ask a new question. 2] enum QLocalSocket:: SocketOption flags QLocalSocket:: SocketOptions This enum describes the possible options that can be used to connect to a server. Use wakeOne() to wake one randomly selected thread or wakeAll() to wake them all. Type "MyType" has id: 1024 ; register status: true QObject::connect: Cannot queue arguments of type 'MyType' (Make sure 'MyType' is registered using qRegisterMetaType(). Currently I have a 2d array which represents the game board. Registers the type name typeName for the type T. I have a class that is a subclass of QObject that I would like to register as a meta-type. Share. Sorted by: 5. Defining QML Types from C++. My first intuition was to have a class inheriting from rclcpp::Node only with an instance of MainWindow but didn't manage to have it work that way. Using qRegisterMetaType() is actually registering a certain type to QMetaType. . . It will return the same result if it was called before. qRegisterMetaType<foo::FooState>(); Question. And this should be used for each exe/dll instance. – 2、注册方法：在当前类的顶部包含：#include <QMetaType>，构造函数中加入代码：qRegisterMetaType<MyClass>("Myclass")； 3、Myclass的引用类型需单独注册：qRegisterMetaType<MyClass>("Myclass&")； A. Hello, i have the following warning and i would like to ask how can i fix it. QTextCursor contains information about both the cursor's position within a QTextDocument and any selection that it has made. To register VideoMeta you need to call qRegisterMetaType<VideoMeta>(). 5] int qRegisterMetaType (QMetaType meta) Registers the meta type meta and returns its type Id. show(); int functionIndex = win. QObject::connect: Cannot queue arguments of type 'SomeUserDefinedType' (Make sure 'SomeUserDefinedType' is registered using qRegisterMetaType(). Use it if you want to use it as a global enumerator and then you need to call the meta-type runtime registration from the library, not from the application. The class is used as a helper to marshall types in QVariant and in queued signals and slots connections. I have gave you below the basic process for a deletion for example. Read and abide by the Qt Code of Conduct. Also, to use type T with the QObject::property () API,. The following code will work similarly: using namespace foo; qRegisterMetaType<MyClass> ("MyClass"); qRegisterMetaType<MyClass> ("foo::MyClass"); For example, the "MyClass" and "foo::MyClass" strings are used to identify argument types when you refer to your signals and slots. I'm not sure how to do this in python but. 则QML中可直接使用 MainController。. This is the same as indexOfMethod (), except that it will return -1 if the method exists but isn't a signal. QModbusDataUnit can be used for read and write operations. Haven't tried it yet but it appears to check the permissions established in the manifest(?). emit (statuses) Share. One of these plugins uses Q_DECLARE_METATYPE on some types that need to be stored in a QVariant. G. It seems QVariant is not direct part of queued connections mechanism. open(wsUrl); without threading the connection works fine. 1,609 4 22 34. qml:17: Error: Unknown method parameter type: const Person*. A QWindow created with the surface type RasterSurface can be used in combination with QBackingStore and QPainter , Qt’s highly optimized 2D vector graphics API. QWaitCondition allows a thread to tell other threads that some sort of condition has been met. ChildAdded and ChildRemoved events are sent to objects when children are added or removed. Call qRegisterMetaType () to make type available to non-template based. Yet, the first line is invisible and this line becomes visible only if we click on it! Very weird! QObject::connect: Cannot queue arguments of type 'QTextCursor'. So in both cases qRegisterMetaType isn't required for the slot to be called and the custom type to be accessible within the slot (i. When data values are exchanged between QML and C++, they are converted by the QML engine to have the correct data types as appropriate for use in QML or C++. call qRegisterMetaType with the name specified, else reading properties. Object::connect: No such slot main_application::input_handler(button_back) Of course, there is, because signature is main_application::input_handler(button_type), and button_back is a value, not type. If the Microsoft compiler was not requiring this, then it was doing it wrong. 1 Answer. Someone may be able to correct me here, but I don't think you should be needing to register the type int&. This function was introduced in Qt 6. Call qRegisterMetaType () to make type available to non-template based functions, such as the queued signal and slot connections. qRegisterMetaTypeしているにもかかわらずQObject::connectでランタイムエラーが出る場合の回避策. However, if I add the const qualifier in front of Person* p in the argument list of test () I get errors from QML at run-time! (i. I am trying to learn Qt and I am attempting to do so by making a little titres game. Note following line #include. Can you show the code that's actually causing the. 二者的联系： QMetaTypeId<TYPE>的类中的成员包含对qRegisterMetaType的调用. Any class or struct that has a public default constructor, a public copy constructor and a public destructor can be registered in QMetaType. ros. constData ()), " qRegisterNormalizedMetaType ", " qRegisterNormalizedMetaType was called with a not normalized type name, please call qRegisterMetaType instead. QObject::connect: Cannot queue arguments of type 'ProcessHandle*const' (Make sure 'ProcessHandle*const' is registered using qRegisterMetaType(). But anyway, it is a good practice to use copyable and self-constructable types for stream operators. ) It still works but point to the fact that I am doing something wrong, and I am not sure that I will keep working when more threads are active. Qt documentation specifically states that qRegisterMetaType<T>() must be called for a type to work in the Qt property system. ; Create a native socket descriptor, instantiate QAbstractSocket, and call setSocketDescriptor() to wrap the native socket. I realize that this actually works when more than one signal of different types is sent, e. ) I have defined MyStruct in an accessible header file: myheader. I have no problem with registering and using C++ enums in QML code. I created a. )" caused by working in threads. I'm writing python library for very simple text output to Qt's QTextBrowser window (stored in window. by using qRegisterMetaType(). 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. Call qRegisterMetaType() to make type available to non-template based functions, such as the queued signal and slot connections. If a field is empty, keep it in the result. I tested your code on Qt 5. Tour Start here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this siteThis macro is used to specialise the template class QMetaTypeId with typename TYPE, in which, a static member function qt_metatype_id () is defined. This replaces the now-deprecated Q_ENUMS and will automatically register the metatype. cpp is void test (const Person* p)) qrc:example. 3. See also insertColumns (), insertRow (), and removeColumn (). karensantana. 3. Hey Something I wanted to follow up as I noticed I'm not the only with the issue. qRegisterMetaType<MyStruct>("MyStruct"); The QImage was not created using an external buffer, but with the (width, height, Format) constructor. Tested on Linux Ubuntu. If any data was written, this function returns true; otherwise false is returned. g. Call this function if you need QLocalSocket to start sending buffered data immediately. Consider the specific case of qRegisterMetaType. Debugging signals and slots connections. Q_DECLARE_METATYPE is only needed for template-based functions. @SGaist if you see the original question I posted the contents of the devicepresence. And once all of them are updated I'd like the Context object to inform QML to update the view. Hi, you can try using a more robust flavor of connect() by adding an argument after the lambda, like this:We will still need to register it with the meta-object system at run-time by calling the qRegisterMetaType() template function before we make any signal-slot connections that use this type. 1 Answer. Otherwise you might be adding duplicate entries to the metatype database each time. This object can then be passed from QML to C++ via. call qRegisterMetaType with the name specified, else reading properties. Also, to use type T with the QObject::property() API, qRegisterMetaType() must be called before it is used, typically in the constructor of the. This function was introduced in Qt 5. runBtn = QtWidgets. This requires the exchanged data to be of a type that is recognizable by the engine. 将C++实现的类在QML中调用的. tag(); // prints MY_CUSTOM_TAG. ) You can read about how to call qml functions from c++. Then you should register your object to use it with QML. call qRegisterMetaType() to register the data type before you call QMetaMethod::invoke(). I have tried registering QTextCursor with qRegisterMetaType, but it doesn't help; Anyone can tell what I am doing wrong, and how to fix that? Many thanks. – folibis. QObject::connect: Cannot queue arguments of type 'QVector<int>' (Make sure 'QVector<int>' is registered using qRegisterMetaType(). It associates a type name to a type so that it can be created and destructed dynamically at run-time. A more complex program sending QSharePointer objects using slots has a similar situation with GDB, that can be reproduced with the previous example. The related type must provide a public default constructor, a public copy constructor and a public destructor to be eligible to be declared as a metatype. The QML engine provides built-in support for a large number. Did you try to use qRegisterMetaType function? The official manual says: The class is used as a helper to marshall types in QVariant and in queued signals and slots connections. But Q_OBJECT macro handles this automatically. The syntax gets especially interesting when specializing a template function of a. QObject::connect: Cannot queue arguments of type 'uint32_t' (Make sure 'uint32_t' is registered using qRegisterMetaType(). For pointer types, it also requires that the pointed to type is fully defined. QAbstractSocket is the base class for QTcpSocket and QUdpSocket and contains all common functionality of these two classes. ) What I have done is, declare in the main the qRegisterMetatype but it still complaining.