c:55 This looks like some loader initialization mismatch, check debug vs release builds of your application and libraries that are used. Using the macro directly turned out to be impossible. Qt Base (Core, Gui, Widgets, Network,. It manages an insane amount of static variables and sets a static global pointer of. 0 and have problems registering my own class as a QMetaType. So using qRegisterMetaType () you will just trade Q_ENUM () for Q_DECLARE_METATYPE (). due to requirements at my job, I had to revert by build from Qt5. As you already have a typedef for your type, you can simply use Q_DECLARE_METATYPE as in the following example: #include <QtCore> template <typename T> struct Proxy { T data; }; typedef Proxy<QImage> TrayType; Q_DECLARE_METATYPE (TrayType) class Donor : public. Declare new types with Q_DECLARE_METATYPE() to make them available to QVariant and other template-based functions. As the docs state: Declare new types with Q_DECLARE_METATYPE () to make them available to QVariant and other template-based functions. QObject can't be copied and all its descendants can't be copied also. Qt5でシグナルの引数としてユーザー定義型を指定する場合は、 Q_DECLARE_METATYPE と qRegisterMetaType () を使って方の登録を行う必要が. Call qRegisterMetaType() to make type available to non-template based functions, such as the queued signal and slot connections. Step 1 (mark for MOC), build some QObjects That pattern uses Q_PROPERTY and Q_OBJECT and the MoC tool. But there would be no trouble using the QMetaType class or using qRegisterMetaType before creating an instance of QCoreApplication or QApplication. All I want to do is be able to convert this to a byte array in order to send on a socket, and get the object back (deserialize) on the other end. At the point where I want to read the list, I only care about (and know) the fact that the list contains pointers to objects, which have been derived. Learn more about Teams I can't figure out a way to automatically declare a meta type, i. When these files are processed by repc, repc generates both Source and Replica header files. 23k 10 10 gold. I my real world application Context holds a large number of physical quantities (masses, forces, velocities,. Note that for enum types, you no not even need to call qRegisterMetaType () in these cases. Declare new types with Q_DECLARE_METATYPE() to make them available to QVariant and other template-based functions. An alternative would be to wrap shared_ptr<int> in your own class and implement comparison the way you want. uint64; If this is your first visit, be sure to check out the FAQ by clicking the link above. Even though we do not intend to use the type with QVariant in this example, it is good practice to also declare the new type with. Data Type Conversion Between QML and C++. Now, that Q_DECLARE_METATYPE enables the type for Qt template classes and QVariant. @Mark81 Actually you'll probably need only Q_DECLARE_METATYPE as this is done at compile time - exposing the type to the metatype system (I know it is an enum but it's needed for the QVariant and the like). h instead ofQVariant x2; x2. qRegisterMetaType vs. . So using qRegisterMetaType () you will just trade Q_ENUM () for Q_DECLARE_METATYPE (). [edit] forgot to mention that you also have to use a worker object. The object it returns should also be a member of the factory class. ", which suggests it is only for classes and structs. 4 which does not support all C++11 features. Note that if you intend to use the type in queued signal and slot connections or in QObject's property system, you also have to call qRegisterMetaType() since the names are resolved at runtime. In fact, all Qt classes derived from QObject (direct or indirect) use this macro to declare their copy constructor and assignment operator to be private. Share. cpp. This requires the exchanged data to be of a type that is recognizable by the engine. To copy to clipboard, switch view to plain text mode. // This primary template calls the -Implementation, like all other specialisations should. SocketState is not a registered metatype, so for queued connections, you will have to register it with Q_DECLARE_METATYPE() and qRegisterMetaType(). uint64; If this is your first visit, be sure to check out the FAQ by clicking the link above. Our first stop for registrations always is the macro Q_DECLARE_METATYPE. I read a bit and it seems that Q_DECLARE_SMART_POINTER_METATYPE is supposed to allow this to work. qt. The class is used as a helper to marshall types in QVariant and in queued signals and slots connections. e. Call qRegisterMetaType() to make types available to non-template based functions, such as the queued signal and slot connections. A separate point for your own benefit. Share Follow edited Apr 29, 2013 at 7:21 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. See also state(). cpp. Any class or struct that has a public default constructor, a public copy constructor, and a. Type is not registered, please use the Q_DECLARE_METATYPE macro to make it known to Qt's meta-object system. E. 如果非QMetaType内置类型要. Learn more about Teams Declaring a meta type. } But you'll most likely need to abstract the Q_DECL_EXPORT part so it is a Q_DECL_IMPORT in right circumstances, as described in Creating Shared Libraries. Don't use Q_DECLARE_METATYPE and qRegisterMetaType for your QObject enum. Some structure need to be registered to be queued in asynchronous signals using qRegisterMetaType<T>(name), such as signal which passes QVector<int>. 8 and it all went well with a few function changes, except I got QMetaProperty::read: Unable to handle unregistered datatype errors all over. This allows me to use this type in a Q_PROPERTY, this all. Last updated at 2016-07-08 Posted at 2015-11-16. c:55 This looks like some loader initialization mismatch, check debug vs release builds of your application and libraries. Returns the internal ID used by QMetaType. ) What I'm trying to do is send a signal containing two cv::Mat images from a QThread to the main thread, so that I can display the output. 0. There's no compile time error, but when I run. Note that if you intend to use the type in queued signal and slot connections or in QObject 's property system, you also have to call qRegisterMetaType () since the names are resolved at runtime. Then you should register your object to use it with QML. According to the Qt docs for qRegisterMetaType "Any class or struct that has a public default constructor, a public copy constructor, and a public destructor can be registered. The file (called a "rep" file) uses a specific (text) syntax to describe the API. Normally, you would only register the pointer form if your class cannot be copied, as in the case of QObject and derivatives, but. To use the type T in QVariant, using Q_DECLARE_METATYPE() is sufficient. The reasoning is found in the discussion on Identity vs Value on the Qt Object Model page. It associates a type name to a type so that it can be created and destructed dynamically at run-time. To start viewing messages, select the forum that you want to visit from the selection below. So you can call it from your constructor. J. See also state() and Creating Custom Qt Types. Join Date Mar 2010 Posts 69 Thanks 8 Thanked 1 Time in 1 Post Qt products Platforms} Q_DECLARE_METATYPE(Topic) In main, I have included this: qRegisterMetaType<Topic>("Topic"); When propagating these elements from c++ to QML, everything is working. Adding a Q_DECLARE_METATYPE() makes the type known to all template based functions, including QVariant. Adding a Q_DECLARE_METATYPE() makes the type known to all template based functions, including QVariant. 4 which does not support all C++11 features. 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、自定MyDataType 类型，在这个类型的顶部包含：#include <QMetaType>. That said, your stack trace is really strange: _dl_debug_initialize (ldbase=4294967292, ns=1095236752) at dl-debug. QList of Custom Objects. See also. Qt is throwing an exception because it doesn't know how to store the shared_ptr onto a QDataStream. To start viewing messages, select the forum that you want to visit from the selection below. Your Matrix type is not copiable, thus you can't use Q_DECLARE_METATYPE on it. I'm confused by this error, as the documentation states (emphasis mine): Returns the meta type id of type T at compile time. That class receives a list of variants (wrapping various data) and converts those variants into a binary stream using QDataStream >. in a header file and call @qRegisterMetaType<std::unique_ptr<Thing>> ();@ before your signal and slots are used. This results in access violations when Qt. Q_DECLARE_METATYPE () doesn't actually register the type; you must still use qRegisterMetaType () for that, particularly if you intend to use the type in signal and slot connections. That's probably there, as qRegisterMetaType () wouldn't compile otherwise. Declare new types with Q_DECLARE_METATYPE() to make them available to QVariant and other template-based functions. ) summary refs log tree commit diff statsFoo and Foo* are different types and need to be registered separately. Couple of points: 1) I would use QScriptEngine::newObject() instead of newQObject() for the namespace 2) I would not use a QObject subclass for the data entry if possible, only the prototype has to be. I want to use my objects as QVariants and for queued connections. Note that you are technically lying to the meta type system. } But you'll most likely need to abstract the Q_DECL_EXPORT part so it is a Q_DECL_IMPORT in right circumstances, as described in Creating Shared Libraries. qRegisterMetaType vs. Did you also check the Q_DECLARE_METATYPE macro ?我发现qt5怎么不需要通过q_declare_metatype声明自定义的结构体，也能编译通过，使用正常啊？！！ 估计是多线程传递时，才需要使用q_declare_metatype。另外，看样子q_declare_metatype和qvariant要搭配使用。1 Answer. h" class B : public QObject { Q_OBJECT Q_PROPERTY(A* A1 READ getA1 WRITE setA1) Q_PROPERTY(A* A2 READ getA2 WRITE setA2) public: static A A1;. 【2】使用方法（声明 和 注册自定义数据类型）. In short, I get following error: QObject::connect: Cannot queue arguments of type 'cv::Mat' (Make sure 'cv::Mat' is registered using qRegisterMetaType (). 0. Sorted by: 1. Q_DECLARE_METATYPE(Pkg) and this does not give compile errors, but in my main. Make a typedef for QSharedPointer<UserDataType>, and use both Q_DECLARE_METATYPE as well as qRegisterMetaType () to register it for use. Because Foo is not derived from QObject and QVariant only supports polymorphism for QObject -derived types. hpp and qRegisterMetaType<quint32>("quint32"); in both the Constructors of Class1 and Class2. w/out GUI module you wouldn't have any of those types available). Add qRegisterMetaType and qDBusRegisterMetaType calls to enable the framework to work with the custom type. So, whatever Q_DECLARE_METATYPE is doing cannot be done by writing a function call. 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. . More. the type name must be specified without the class, as in. your custom type definition. class Test : public QWidget { Q_OBJECT public: Test(); signals: public slots: void setAppData(QList<QIcon> icons, QStringList names, QStringList versions, QStringList publishers, QString installLocation, QStringList uninstallLocations); private: }; Q_DECLARE_METATYPE(QIcon) The same issue is still present. Equivalent to Q_DECLARE_METATYPE(TYPE *) and Q_DECLARE_METATYPE(QQmlListProperty<TYPE>) QML_DECLARE_TYPEINFO (Type, Flags) Declares additional properties of the given Type as described by the specified Flags. As said in int qRegisterMetaType () documentation: To use the type T in QVariant, using Q_DECLARE_METATYPE () is sufficient. no I didn't, do I need to put in the file generated by repc or I can put it anywhere ? – Houss_gc. The ENUM type. You can make them known ( Q_DECLARE_METATYPE ), however you can't register them as QML type. After googling this, I found this correspondence, which was only available through a third party archival site as google. uint64; If this is your first visit, be sure to check out the FAQ by clicking the link above. e. The Q_DECLARE_METATYPE() macro and qRegisterMetaType() function documentation contain more detailed information about their uses and limitations. Q_DECLARE_METATYPE ( blabla* ) Also qRegisterMetaType<T> () is only required for sending your object through queued signal/slot connections. until today. Additionally Qt5 always refers to Q_DECLARE_METATYPE, saying that qRegisterMetaType is only when you want to. 2 Answers. Note that if you intend to use the type in queued signal and slot connections or in QObject 's property system, you also have to call qRegisterMetaType () since the names are resolved at runtime. Q_DECLARE_METATYPE accepts objects with public constructor, copy constructor and destructor. Using the Q_DECLARE_METATYPE () macro 2. It would look something like this: Q_DECLARE_METATYPE (MyNamespace::MyClass::MyEnum) However, the Q_DECLARE_METATYPE macro would expand to the following call to qRegisterMetaType: qRegisterMetaType< MyNamespace::MyClass::MyEnum > ("MyNamespace::MyClass::MyEnum",. This won't work because you can't use qMetaTypeId<> () before Q_DECLARE_METATYPE<>. no unexpected garbage. Otherwise your signals and slots connected used the old mechanism (with macros SIGNAL and SLOT) that require queueing of the parameters won't know how to do so. 1. To make the type known to this class, we invoke the Q_DECLARE_METATYPE () macro on the class in the header file where it is defined: This now makes it possible for Message values to be stored in QVariant objects and retrieved later. void Message:: registerMetaType {qRegisterMetaType < Message >. The class is used as a helper to marshall types in QVariant and in queued signals and slots connections. 6. It associates a type name to a type so that it can be created and destructed dynamically at run-time. This function was introduced in Qt 4. Any class or struct that has a public default constructor, a public copy. g. To make the custom type generally usable with the signals and slots mechanism, we need to perform some extra work. See also state() and Creating Custom Qt Types. I however have a scenario where I want to declare such an object in qml and transmit it to the c++. With Q_DECLARE_METATYPE and without qRegisterMetaType: No warning, slot is called With Q_DECLARE_METATYPE and with qRegisterMetaType: No warning, slot is called. See also state() and Creating Custom Qt Types. Research The QMetaType class manages named types in the meta-object system. Original Question. and Q_DECLARE_METATYPE uses qRegisterMetaType() internally. It is only useful to the code that follows it, in the same file. You may have to register before you can post: click the register link above to proceed. If you want both, then register both. I have declared all the types with Q_DECLARE_METATYPE, Q_OBJECT and the properties with Q_PROPERTY with the proper getters and setters. Q_DECLARE_OPAQUE_POINTER (PointerType) This macro enables pointers to forward-declared types (PointerType) to be registered with QMetaType using either Q_DECLARE_METATYPE() or qRegisterMetaType(). Since \c{MyStruct} is now known to QMetaType, it can be used in QVariant: Some types are registered automatically and do not need this macro: /*! This macro makes the container \a Container known to QMetaType as a sequential. QVariantList MyClass::getFooCollection (void) const { QVariantList list; for (const auto& l: fooCollection_) { list. Execute qRegisterMetaType<QItemSelection> (); before it is used as such, e. +50. To use the type T in QVariant, using Q_DECLARE_METATYPE() is sufficient. If you only want to store pointer to Foo with the metatype system, then use qRegisterMetaType<Foo *> ();. hpp which is included in Class1. You may have to register before you can post: click the register link above to proceed. Q_DECLARE_METATYPE与qRegisterMetaType学习. Share Improve this answer Follow answered Jul 23, 2014 at 15:37. I'd understood if i want to pass my custom type like struct or so, but it is essential type. Adding a Q_DECLARE_METATYPE() makes the type known to all template based functions, including QVariant. Also, this Q_DECLARE_METATYPE(SharedTestClass) shouldn't be needed. ) is supported. QVariant v = QVariant::fromValue<cMyClass>(MyObject); However, as soon as I use Q_DECLARE_METATYPE, I get errors about using a deleted function. nyaruko. See also state () and Creating Custom Qt Types . See also Thread Support in Qt, QObject::connect(), qRegisterMetaType(), and Q_DECLARE_METATYPE(). QLocalSocket. Improve this answer. uint64; If this is your first visit, be sure to check out the FAQ by clicking the link above. I. Normally, you would only register the pointer form if your class cannot be copied, as in the case of QObject and derivatives, but. To make the custom type. QtCore. Now, that Q_DECLARE_METATYPE enables the type for Qt template classes and QVariant. Hello, Can someone tell me about how to register a metatype in pyqt5. There's no such thing as a "const reference" because references are always const -- you can't reseat them. To use the type T in queued signal and slot connections, qRegisterMetaType<T>() must be called before the first connection is established. 1 Answer. But this is all useless if you are not using templates. One way to work around this is for example having a helper class (singleton or context property) with. Don't use Q_DECLARE_METATYPE and qRegisterMetaType for your QObject enum. Returns true if convert can convert from fromType to toType. 1. Obviously, a call to qRegisterMetaType<T>(. Obviously then you would not do registerComparator (). Q_DECLARE_METATYPE(TYPEDEF) Q_DECLARE_METATYPE(TYPEDEF) mainwindow. EDIT: When you convert your class to QVariant it uses a. The id is constexpr in the special case of Qt built-in types only. See also. You may have to register before you can post: click the register link above to proceed. Email This BlogThis! Share to Twitter Share to Facebook Share to Pinterest. Q_DECLARE_METATYPE QMetaType::type. So you can call it from your constructor. 1 Answer. 基本理解. Adding a Q_DECLARE_METATYPE() makes the type known to all template based functions, including QVariant. Is your Q_DECLARE_METATYPE in a header file or an implementation file? Incidentally, there is a mistake in TreeItem. You should use qmlRegisterType function for that. 如果要使自定义类型或其他非QMetaType内置类型在QVaiant中使用，必须使用该宏。. Than I did read this copy constructor of derived QT class and the answer by BЈовић. qRegisterMetaType<cv::Mat>(); Modified: qRegisterMetaType< Mat >("Mat");The code generated by repc creates a Q_GADGET class for each POD, with corresponding Q_PROPERTY members for each type defined for the POD. 4. 步骤： (以自定义MyDataType类型为例）. Thus you need to use the runtime check QMetaType::type (). Make sure you call it from within a method. QtCore. 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. int videoSourceMetaTypeId = qRegisterMetaType< VideoSource > ();Declare new types with Q_DECLARE_METATYPE() to make them available to QVariant and other template-based functions. QAbstractSocket::SocketState is not a registered metatype, so for queued connections, you will have to register it with Q_REGISTER_METATYPE() and qRegisterMetaType(). Adding a Q_DECLARE_METATYPE() makes the type known to all template based functions, including QVariant. QAbstractSocket::SocketState is not a registered metatype, so for queued connections, you will have to register it with Q_DECLARE_METATYPE() and qRegisterMetaType(). Basically, I created a library containing a type: struct MyCustomType {. 文章目录 Q_DECLARE_METATYPE qRegisterMetaType Q_DECLARE_METATYPE 使用Q_DECLARE_METATYPE标记自定义类型，可以让QMetaType查询到类型，也可以让QVariant识别。 qRegisterMetaType 在main函数中使用qRegisterMetaType注册自定义类型到元对象系统中,可在跨线程的信号槽中进行参数传递。I'm using Qt5 and qRegisterMetaType is not documented anymore, so I'm not sure if it's deprecated. Assuming base and derived are Q_GADGETs you want to get a static member. Q&A for work. ) which are updated by simulation code. qRegisterMetaType<Subclass> ("Subclass") also doesn't work. See also state() and Creating Custom Qt Types. 14. 手册中告诉我们，执行这个的时候，模板参数T必须用 Q_DECLARE_METATYPE() 声明过 能猜到原因吗？注意看前面 Q_DECLARE_METATYPE() 代码， 对了。类中的成员函数qt_metatype_id中包含对qRegisterMetaType(typeName)的调用 这儿就是辗转调用了这个带参数. c:55 This looks like some loader initialization mismatch, check debug vs release builds of your application and libraries. QAbstractSocket::SocketState is not a registered metatype, so for queued connections, you will have to register it with Q_REGISTER_METATYPE() and qRegisterMetaType(). I store them in QVariant :. 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 signal-slot communication or need to create and destroy objects of the custom type at run-time. QML Qvariant from custom class. You may have to register before you can post: click the register link above to proceed. If I get AnotherQGadgetClass via getter and change it's properties, the setters are called and. One of these plugins uses Q_DECLARE_METATYPE on some types that need to be stored in a QVariant. The Rep lica C ompiler (repc) generates QObject header files based on an API definition file. Adding a Q_DECLARE_METATYPE() makes the type known to all template based functions, including QVariant. Secondly, your linker (MSVC) complains that it can't find the metaObject for your ErrorHandler enum, which is normal as it is not exported from the. qRegisterMetaType you'll need if creating objects by class name dynamically, and it seems for queued connections,. I pass the MyClass pointer to the streaming operator and only stream things like QString, QPointF, etc. I need to call the Q_DECLARE_METATYPE() to pass the smart pointer. Also, this Q_DECLARE_METATYPE(SharedTestClass) shouldn't be needed. See also. What is the point of emitting a QSharedPointer? The worker thread reads the files computes the data allocates and fills the memory with data, wraps it in QSharedPointer and passes it to the mainThread, which is used for plotting. container. See QMetaType docs for more information. Note: This function is thread-safe. This is not the case, since the following succeeded: @QMetaType::type("MyClass"); // success@. Using the qRegisterMetaType () function The Q_DECLARE_METATYPE () macro is the preferred way to declare a variable in Qt. (Make sure 'MyStruct' is registered using qRegisterMetaType (). 被 Q_DECLARE_METATYPEQ 标记的类型可以让Q MetaType 查询到类型，也可以让QVariant识别到。 struct MyStruct { QString name; }; Q_DECLARE_METATYPE(MyStruct) 若对象包含在自定义的命名空间中时，注册时要带上完整的命令空间. As the docs state: Declare new types with Q_DECLARE_METATYPE () to make them available to QVariant and other template-based functions. Actually, they are declared, but in a private section with the macro Q_DISABLE_COPY(). cpp I have to do: qRegisterMetaType<Pkg>("Pkg"); and this does not give errors too, but when I try to create a QVariant(Pkg) I get lots of errors like:cardio63 26 Jan 2016, 10:19. type() typeName() PySide6. Call qRegisterMetaType() to make types available to non-template based functions, such as the queued signal and slot connections. Q_DECLARE_METATYPE(TYPEDEF) Q_DECLARE_METATYPE(TYPEDEF) mainwindow. To start viewing messages, select the forum that you want to visit from the selection below. It does not say anything about registering the type. That's created by this macro. @SGaist Yes, I am using it with QVariant, mostly with QSettings to save and retrieve data easily by overriding QDataStream operators. First of all, you always need to declare your meta type: Q_DECLARE_METATYPE (foo::MyClass) It works at compile time, so there are no limitations on how you refer to your class. That said, your stack trace is really strange: _dl_debug_initialize (ldbase=4294967292, ns=1095236752) at dl-debug. There's also no need for that typedef, it only makes the code less readable. This also makes the type available for queued. Franzk 26 May 2011, 06:59. Step 2 (meta type Declare macro), if needed, describe your custom type/class to things like QVariant, QDebug and other "support" systems used everywhere on QObjects. See also state() and Creating Custom Qt Types. h" class Context : public QObject { Q_OBJECT Q_PROPERTY (MyGadget* gadget READ gadget CONSTANT) public: explicit Context () : QObject {nullptr} { } MyGadget* gadget () { return &_gadget; } private. no unexpected garbage. Greetings. I tried and it looks like it's possible to register an enum type with Q_DECLARE_METATYPE or qRegisterMetaType and use it the same way. h. To use the type T in queued signal and slot connections,. The class is used as a helper to marshall types in QVariant and in queued signals and slots connections. Got a similar example working without explicitly calling qRegisterMetaType() just by removing the semicolon from the line Q_DECLARE_METATYPE(StateMachine::state) – user666412 Sep 21, 2015 at 14:17Additional types can be registered using qRegisterMetaType() or by calling registerType(). In some cases in Qt 4, it is also necessary to use the qRegisterMetaType method. 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. e. Jun 13, 2021 at 19:37. Q_DECLARE_METATYPE(NSP::MyStruct) qRegisterMetaTypeIt associates a type name to a type so that it can be created and destructed dynamically at run-time. queued connections. To use the type T in queued signal and slot connections, qRegisterMetaType () must be called before the first connection is established. If you want both, then register both. 1. I only care about runtime. 1. The problem of owner ship of the memory is avoided. in a header file and call @qRegisterMetaType<std::unique_ptr<Thing>> ();@ before your signal and slots are used. Q_DECLARE_METATYPE. You can also use QMetaEnum::fromType() to get the QMetaEnum. This now makes it possible for Message values to be stored in QVariant objects and retrieved later. Inheritance diagram of PySide6. 8. That said, your stack trace is really strange: _dl_debug_initialize (ldbase=4294967292, ns=1095236752) at dl-debug. c:55 This looks like some loader initialization mismatch, check debug vs release builds of your application and libraries. Note that you are technically lying to the meta type system. Note that if you intend to use the type in queued signal and slot connections or in QObject's property system, you also have to call qRegisterMetaType() since the names are resolved at runtime. I need to call the Q_DECLARE_METATYPE() to pass the smart pointer. It is often easier and cleaner to define an ENUM inside a class (see ENUM), but if you need a standalone enum type, using the ENUM keyword outside of a class definition can be. JulienMaille @kshegunov last edited by JulienMaille . The reason to need this is usually that Q_PROPERTY is used with a metatype which is not built-in (types such as int and QString are built-in and don’t. You may have to register before you can post: click the register link above to proceed. I placed Q_DECLARE_METATYPE (DataPoint) after the class definition. There is no contradiction, because you can't register QObject descendants with Q_DECLARE_METATYPE. Q_DECLARE_METATYPE QMetaType::type. . Reply Quote. I think you need to add an explicit export/import directive to the QT_NAMESPACE macro. Do do you register the meta type with the call qRegisterMetaType("your custom meta type")? 1 Reply Last reply Reply Quote 0. x however, the code generated by moc will call qRegisterMetaType for you if moc can determine that the type may be registered as a meta-type. Note that if you intend to use the type in queued signal and slot connections or in QObject 's property system, you also have to call qRegisterMetaType () since the names are resolved at runtime. Macros Detailed Description The QMetaType class manages named types in the meta-object system. My workround was to explicitly cast the enum values to int when passing them onto a function requiring a QVariant type, in my case. I read a bit and it seems that Q_DECLARE_SMART_POINTER_METATYPE is supposed to allow this to work. –To copy to clipboard, switch view to plain text mode. 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. I've registered my class with: @Q_DECLARE_METATYPE(MyClass);@ and. The object it returns should also be a member of the factory class. Q_DECLARE_METATYPE(NSP::MyStruct) qRegisterMetaTypeIt associates a type name to a type so that it can be created and destructed dynamically at run-time. The class is used as a helper to marshall types in QVariant and in queued signals and slots connections. @Q_DECLARE_METATYPE (std::unique_ptr<Thing>);@. QLocalSocket::SocketState is not a registered metatype, so for queued connections, you will have to register it with Q_DECLARE_METATYPE() and qRegisterMetaType(). I just tried. 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. [virtual] QAbstractSocket:: ~QAbstractSocket Destroys the socket. uint64; If this is your first visit, be sure to check out the FAQ by clicking the link above. The Custom Type, Custom Type Sending and Queued Custom Type examples show how to implement a custom type with the features outlined in this document. 0. hi, I always after application running, receive debug text of: QObject::connect: Cannot queue arguments of type 'MyStruct'. " –If I declare Class B as follows, it works fine, despite the fact that I haven't done Q_DECLARE_METATYPE for the pointer: #include <QObject> #include <QMetaType> #include "a. Also, this Q_DECLARE_METATYPE(SharedTestClass) shouldn't be needed. You could try using registerConverter () to allow implicit conversion of the shared_ptr<int> to a regular int, and compare them that way. [override virtual] bool QAbstractSocket:: waitForBytesWritten (int msecs = 30000) Reimplements:. There's also no need for that typedef, it only makes the code less readable. struct StandardData { int EmpId; QString Name; }; Q_DECLARE_METATYPE (StandardData) Additionally, you might need to call qRegisterMetaType. I have an application that requires use of both Qt 3D and the QCustomPlot library. The struct is declared in my worker class, which is inside a namespace. Also, this Q_DECLARE_METATYPE(SharedTestClass) shouldn't be needed. type() typeName() PySide6. Unsure if my idea would work, I created a DataPoint class marked with Q_GADGET with three properties defined using Q_PROPERTY. Hope it. When I try to simply connect signalslot with such QVector as argument programm tells during run that this metatype should be registered (though QVector, QSharedPointer and class inherited from QObject should be registered automatically. 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. Hello Ladies and Gentlemen. Q_DECLARE_METATYPE(TYPEDEF) Q_DECLARE_METATYPE(TYPEDEF) mainwindow. QList<T> isn't really a pre-defined variant type (except QList<QVariant>) so it technically resolves to a QMetaType::UserType. It's not enough to get reflection features out of a type this way (it does not create a QMetaObject), so for the thing to be useful at all you need at least Q_GADGET in both base and derived classes.