I have an application that requires use of both Qt 3D and the QCustomPlot library. c:55 This looks like some loader initialization mismatch, check debug vs release builds of your application and libraries that are used. You could also Q_DECLARE_METATYPE to register your custom type and then use qMetaTypeId() to get the metaType id. If you only want to store pointer to Foo with the metatype system, then use qRegisterMetaType<Foo *> ();. You don't pass around copies of QObject derived types because it is not copyable. However, it does appear (at least to me) that you're trying to debug a release build of the application. append (QVariant::fromValue (l)); } return list; } The metatype system declaration and registration you have. struct Matrix { double data [4] [4]; }; Ideally you should be using eigen3. You should use qmlRegisterType function for that. 1 Answer. The problem of owner ship of the memory is avoided. w/out GUI module you wouldn't have any of those types available). I read on documentation that Q_DECLARE_METATYPE makes available type to QVariant, for example (I got it from documentation): @ struct MyStruct { int i;. 4 which does not support all C++11 features. This also makes the type available for queued. It associates a type name to a type so that it can be created and destructed dynamically at run-time. Normally, you would only register the pointer form if your class cannot be copied, as in the case of QObject and derivatives, but. 0. So I am doing this: Qt Code: Switch view. There's also no need for that typedef, it only makes the code less readable. 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. The class is used as a helper to marshall types in QVariant and in queued signals and slots connections. uint64; If this is your first visit, be sure to check out the FAQ by clicking the link above. 基本理解. It manages an insane amount of static variables and sets a static global pointer of. The object it returns should also be a member of the factory class. qt. First of all you need to declare your custom object for Qt metatype system. QVariant x2 = QVariant::fromValue( x1); To copy to clipboard, switch view to plain text mode. This also makes the type available for queued. It associates a type name to a type so that it can be created and destructed dynamically at run-time. h instead ofQVariant x2; x2. Step 1 (mark for MOC), build some QObjects That pattern uses Q_PROPERTY and Q_OBJECT and the MoC tool. This makes them suitable for use with both static properties declared using the Q_PROPERTY() macro in class definitions and dynamic properties created at run-time. 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. Call qRegisterMetaType () to make type available to non-template based functions. But I really would like to know the correct way to solve this problem; one where it is not possible to modify the template classes. See also. int videoSourceMetaTypeId = qRegisterMetaType< VideoSource > ();QAbstractSocket::SocketState is not a registered metatype, so for queued connections, you will have to register it with Q_DECLARE_METATYPE() and qRegisterMetaType(). To use the type T in queued signal and slot connections, qRegisterMetaType () must be called before the first connection is established. Don't use Q_DECLARE_METATYPE and qRegisterMetaType for your QObject enum. @kshegunov said in Undocumented automatic metatype registration in Qt6?: Your original code (in the top-mentioned topic) assumes std::unique_ptr is copyable, which it isn't, so it can not ever be a metatype. Firstly, you shouldn't need to use Q_DECLARE_METATYPE (or qRegisterMetaType) with the enum at all, this is handled by the moc. 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. That was it for Q_DECLARE_METATYPE, but you would still need to call qRegisterMetaType to use these type in a Q_PROPERTY or as a parameter in a signal/slot queued connection. 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. Returns the internal ID used by QMetaType. The QML engine provides built-in support for a. 基本理解. QVariantList MyClass::getFooCollection (void) const { QVariantList list; for (const auto& l: fooCollection_) { list. I have a few instances of QVector<MyClass> which I want them to be exposed to QScriptEngine. e. " Yet types like QVariantMap are themself typedefs. A. Constantin. 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;. Q_DECLARE_METATYPE vs qRegisterMetaType for non global namespace classes. 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",. Type is not registered, please use the Q_DECLARE_METATYPE macro to make it known to Qt's meta-object system. Does your code ever call qRegisterMetatype() or use Q_DECLARE_METATYPE()? 10th November 2014, 06:23 #3. The class is used as a helper to marshall types in QVariant and in queued signals and slots connections. The Custom Type and Queued Custom Type examples show how to implement a custom type with the features outlined in this document. Re: Qt warning of type conversion already registered Originally. Execute qRegisterMetaType<QItemSelection> (); before it is used as such, e. See full list on doc. To register. To enable using the type in queued signals and such, there also needs to be a corresponding call: qRegisterMetaType<foo::FooState>(); Question. An alternative would be to wrap shared_ptr<int> in your own class and implement comparison the way you want. There's no need to call qRegisterMetaType that many times, once is enough. cpp. However, as you need the type to be. There's no compile time error, but when I run. To use the type T in queued signal and slot connections, qRegisterMetaType () must be called before the first connection is established. Then you should register your object to use it with QML. qRegisterMetaType() docs say: Any class or struct that has a public constructor, a public copy constructor, and a public destructor can be registered. That said, your stack trace is really strange: _dl_debug_initialize (ldbase=4294967292, ns=1095236752) at dl-debug. Passing across threads (queued connection) will copy the QVector in either case, but the const will remind you that you cannot alter the original QVector in. Share. The reasoning is found in the discussion on Identity vs Value on the Qt Object Model page. Believing an Question from 2010 and the Qt Documentation, the operator==() doesn't work with custom types. [virtual] QLocalSocket:: ~QLocalSocket Destroys the socket, closing the connection if necessary. But because QUuid stores its content as a QByteArray which is already supported by QVariant, you. . 1 Answer Sorted by: 21 Objects are copied when put into a QVariant, but QObject derived classes cannot be copied, so the solution is to use a pointer to your. g. Warning: This function is useful only for registering an alias (typedef) for every other use case Q_DECLARE_METATYPE and qMetaTypeId () should be used instead. As you have already found out, you must use Q_DECLARE_METATYPE to make the type known to Qt. 14. qRegisterMetaType vs. since it is a runtime registration. To register a type, it must be declared as a meta-type with the Q_DECLARE_METATYPE() macro, and then registered as in the following example:. Q_DECLARE_METATYPE. This is by design. To start viewing messages, select the forum that you want to visit from the selection below. QMetaType registerNormalizedTypedef normalizedTypeName, type: metaType ); return. Type is declared with Q_DECLARE_METATYPE and registered with qRegisterMetaType. To start viewing messages, select the forum that you want to visit from the selection below. ) summary refs log tree commit diff statsFoo and Foo* are different types and need to be registered separately. . There's no such thing as a "const reference" because references are always const -- you can't reseat them. ) 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. // But the split allows to. jsulm Lifetime Qt Champion @shivaVMC last edited by . You can't with Q_GADGETS. @Wieland Thanks. 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. uint64; If this is your first visit, be sure to check out the FAQ by clicking the link above. F. 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. 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. Connect and share knowledge within a single location that is structured and easy to search. You can also use QMetaEnum::fromType() to get the QMetaEnum. What worries me is that. Also, this Q_DECLARE_METATYPE(SharedTestClass) shouldn't be needed. As a result, if the library connects a D-Bus signal to a slot with a signature "void mySlot (MyType)", it is. PySide6. Sorted by: 3. Adding a Q_DECLARE_METATYPE() makes the type known to all template based functions, including QVariant. The struct is declared in my worker class, which is inside a namespace. That said, your stack trace is really strange: _dl_debug_initialize (ldbase=4294967292, ns=1095236752) at dl-debug. With Q_DECLARE_METATYPE and without qRegisterMetaType: No warning, slot is called With Q_DECLARE_METATYPE and with qRegisterMetaType: No warning, slot is called. 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: Q_DECLARE_METATYPE (Message). 1. Returns the internal ID used by QMetaType. So I played around, copied the original macro and adapted it a bit: @. Consider the specific case of qRegisterMetaType. If the pointer stored in the QVariant can be qobject_cast to T, then that result is returned. 4] QString QWebSocket:: subprotocol const. . 6. The Q_DECLARE_METATYPE () macro also makes it possible for these values to be used as arguments to signals, but only in direct signal-slot connections. Adding a Q_DECLARE_METATYPE() makes the type known to all template based functions, including QVariant. Any idea what I'm missing please? BTW, no problem at all using Schedule in QMetaProperty or QVariant. Here you can see that the macro expands to nothing. Learn more about Teams I can't figure out a way to automatically declare a meta type, i. To start viewing messages, select the forum that you want to visit from the selection below. complains that the metatype isn't registered. 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. With Q_DECLARE_METATYPE and without qRegisterMetaType: No warning, slot is called With Q_DECLARE_METATYPE and with qRegisterMetaType: No warning, slot is called. So you can call it from your constructor. uint64; If this is your first visit, be sure to check out the FAQ by clicking the link above. Alt. You may have to register before you can post: click the register link above to proceed. You could try using registerConverter () to allow implicit conversion of the shared_ptr<int> to a regular int, and compare them that way. @Q_DECLARE_METATYPE (std::unique_ptr<Thing>);@. Read and abide by the Qt Code of Conduct. 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. void Message:: registerMetaType {qRegisterMetaType < Message >. Also, to use type T with the QObject::property () API, qRegisterMetaType () must be. qRegisterMetaType vs. That. Re: Q_DECLARE_METATYPE vs qRegisterMetaType for non global namespace classes (QTest) The reason for this behavior might be caused by the fact that runtime signal/slot connections are checked by string manipulation - both Q_DECLARE_METATYPE, SIGNAL, SLOT macros and 'moc' are (among other things) converting type-names to text and pass it along. See also state () and Creating Custom Qt Types . I read a bit and it seems that Q_DECLARE_SMART_POINTER_METATYPE is supposed to allow this to work. statement to the header file containing. If I get AnotherQGadgetClass via getter and change it's properties, the setters are called and. So, if you had a custom type FooType, you'd put the Q_DECLARE_METATYPE directly after the declaration, and in. 8. QLocalSocket::SocketState is not a registered metatype, so for queued connections, you will have to register it with Q_DECLARE_METATYPE() and qRegisterMetaType(). 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. Now I want to read this property with Qt's meta object system. 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. With Q_DECLARE_METATYPE and without qRegisterMetaType: No warning, slot is called With Q_DECLARE_METATYPE and with qRegisterMetaType: No warning, slot is called. From the docs: int qRegisterMetaType ( const char * typeName ) Registers the type name typeName to the type T. Note that you are technically lying to the meta type system. int videoSourceMetaTypeId = qRegisterMetaType< VideoSource > ();Declare new types with Q_DECLARE_METATYPE() to make them available to QVariant and other template-based functions. If such a connection is made, and a signal triggered, the runtime warning will be shown: QObject::connect: Cannot. Q_DECLARE_METATYPE与qRegisterMetaType学习. That said, your stack trace is really strange: _dl_debug_initialize (ldbase=4294967292, ns=1095236752) at dl-debug. After googling this, I found this correspondence, which was only available through a third party archival site as google. The QMetaType class manages named types in the meta-object system. uint64; If this is your first visit, be sure to check out the FAQ by clicking the link above. Also Q_DECLARE_METATYPE does not register a type, but declares it. ) 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. . I believe this is related to the fact that. With Q_DECLARE_METATYPE and without qRegisterMetaType: No warning, slot is called With Q_DECLARE_METATYPE and with qRegisterMetaType: No warning, slot is called. 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. [virtual] QAbstractSocket:: ~QAbstractSocket Destroys the socket. You may have to register before you can post: click the register link above to proceed. The ones I am registering for are mostly structs for storing data and just a few simple classes. The Q_DECLARE_METATYPE() macro and qRegisterMetaType() function documentation contain more detailed information about their uses and limitations. Call qRegisterMetaType() to make types available to non-template based functions, such as the queued signal and slot connections. [since 6. no I didn't, do I need to put in the file generated by repc or I can put it anywhere ? – Houss_gc. To make the custom type. Returns the internal ID used by QMetaType. Note that you are technically lying to the meta type system. qRegisterMetaType () is called to register the TYPE and generate a TYPE ID. However, if you want to use a type in a pure runtime context, for example in a QML document, the Qt runtime doesn't know the type declared with Q_DECLARE_METATYPE. A separate point for your own benefit. As a workaround, I'm using QVariantMap instead of std::map. The Problem: I want to create an object instance at runtime using QMetaType by the type name. What you made is a const pointer to a non-const T; but top-level consts in function signatures are not part of the function. QtCore. 11. To start viewing messages, select the forum that you want to visit from the selection below. Any errors from Qt's metatype systems are usually due to MOC (the "meta-object compiler"), which reads your header files and generates a "moc" file with metatype information for every class where the Q_OBJECT macro is declared. The Q_DECLARE_METATYPE() macro and qRegisterMetaType() function documentation contain more detailed information about their uses and limitations. Teams. Sorted by: 2. In the header, after the class declaration, outside the namespace, I've included. 0. I also added qRegisterMetaType<DataPoint> () to the initialisation method of my main. Also, this Q_DECLARE_METATYPE(SharedTestClass) shouldn't be needed. Also Q_DECLARE_METATYPE does not register a type, but declares it. Thank you Volker, I had a couple of problems I forgot about the Q_DECLARE_METATYPE(myType); and I don't' think I was never consistent with the global scope specifier. Also, this Q_DECLARE_METATYPE(SharedTestClass) shouldn't be needed. There's also no need for that typedef, it only makes the code less readable. See also. Now, in your registerTypes function, it should be registered like this: qRegisterMetaType<AccReal > ("data::AccReal"); In other words, the typeName string must match exactly the type of the signal argument as it is written there. // - in a header: // - define a specialization of this template calling an out-of. This replaces the now-deprecated Q_ENUMS and will automatically register the metatype. } 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. I only care about runtime instantiation. Accessing an enum stored in a QVariant. Q_DECLARE_METATYPE(MyClass*); That's how Qt handles it with QObject and QWidget. I'm using Qt 5. Adding a Q_DECLARE_METATYPE() makes the type known to all template based functions, including QVariant. Q_OBJECT derived class, inheritance. QObject::connect: Cannot queue arguments of type 'MyStruct'. So using qRegisterMetaType () you will just trade Q_ENUM () for Q_DECLARE_METATYPE (). Any class or struct that has a public constructor, a public copy constructor, and a public destructor can be registered. You may have to register before you can post: click the register link above to proceed. Make your own typedef and do the Q_DECLARE_METATYPE and qRegisterMetatype. Yes, templated types can be used in Qt signal/slots. Assuming base and derived are Q_GADGETs you want to get a static member. 1. Declare new types with Q_DECLARE_METATYPE () to make them available. This function was introduced in Qt 4. Greetings. Your Matrix type is not copiable, thus you can't use Q_DECLARE_METATYPE on it. qRegisterMetaType vs. 3. Adding a Q_DECLARE_METATYPE() makes the type known to all template based functions, including QVariant. Call qRegisterMetaType () to make type available to non-template based. 0. 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. on top of main. 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. J. rep file extension, short for Replica. qRegisterMetaType<Subclass> ("Subclass") also doesn't work. This function was introduced in Qt 6. Declare new types with Q_DECLARE_METATYPE () to make them available. Unsure if my idea would work, I created a DataPoint class marked with Q_GADGET with three properties defined using Q_PROPERTY. . e. QMetaType. no unexpected garbage. Sorted by: 1. QLocalSocket::SocketState is not a registered metatype, so for queued connections, you will have to register it with Q_DECLARE_METATYPE() and qRegisterMetaType(). There is no contradiction, because you can't register QObject descendants with Q_DECLARE_METATYPE. Qt Base (Core, Gui, Widgets, Network,. I'm confused by this error, as the documentation states (emphasis mine): Returns the meta type id of type T at compile time. Per Qt documentation: To use the type T in QVariant, using Q_DECLARE_METATYPE () is sufficient. In my own code, I use Q_DECLARE_METATYPE for classes I want to store. 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. See also state() and Creating Custom Qt Types. Using Qt 3D with QCustomPlot. The class is used as a helper to marshall types in QVariant and in queued signals and slots connections. The QMetaType class manages named types in the meta-object system. One of the overloads is a function template that can be used to create an alias for a type and the form is: qRegisterMetaType<Type> ("alias"); That is, it wants to know the type for which you are declaring something. QLocalSocket::SocketState is not a registered metatype, so for queued connections, you will have to register it with Q_DECLARE_METATYPE() and qRegisterMetaType(). Detailed Description. Original Question. nyaruko. It is more or less explained in the manual for int qRegisterMetaType (const char *typeName) This function requires that T is a fully defined type at the point where the function is called. wysota. You may have to register before you can post: click the register link above to proceed. 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. Question: Is there a way to check at compile-time if qRegisterMetaType<T> () was called for a custom type T? The custom type T needs to be registered in Qt meta-type system in order to be used in e. Re: How to use Q_DECLARE_METATYPE. 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. In my project, MyClass is a cache for multi-dimensional data "point", and it looks like: class MyClass { public: MyClass(); /* Some functions */ private: int m_index; double m_time; QList<int> *m_data; };Firstly, you shouldn't need to use Q_DECLARE_METATYPE (or qRegisterMetaType) with the enum at all, this is handled by the moc. 1 Answer. 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. If the type was not declared with Q_DECLARE_METATYPE (), compilation will fail. Adding a Q_DECLARE_METATYPE() makes the type known to all template based functions, including QVariant. The QMetaType class manages named types in the meta-object system. It looks like one can register a type more than once, specifying different typenames, i. As a workaround, I'm using QVariantMap instead of std::map. That said, your stack trace is really strange: _dl_debug_initialize (ldbase=4294967292, ns=1095236752) at dl-debug. By convention, these files are given a . To start viewing messages, select the forum that you want to visit from the selection below. This results in access violations. 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. See also state() and Creating Custom Qt Types. There's no compile time error, but when I run. The other overload around has almost the same form but for the. uint64; If this is your first visit, be sure to check out the FAQ by clicking the link above. Avoid having to qRegisterMetaType (pointer vs reference), concern about const. You may have to register before you can post: click the register link above to proceed. Detailed Description The QMetaType class manages named types in the meta-object system. And once all of them are updated I'd like the Context object to inform QML to update the view. I only care about runtime. The QMetaType class manages named types in the meta-object system. c:55 This looks like some loader initialization mismatch, check debug vs release builds of your application and libraries that are used. E. 3 to Qt4. EDIT: When you convert your class to QVariant it uses a. You had to use QMetaType::registerComparators () and the other static register functions in QMetaType to actually make use of that functionality, though. Re: How to use Q_DECLARE_METATYPE. Q_DECLARE_METATYPE与qRegisterMetaType学习. The id is constexpr in the special case of Qt built-in types only. Detailed Description. // - in a header: // - define a specialization of this template calling an out-of. That said, your stack trace is really strange: _dl_debug_initialize (ldbase=4294967292, ns=1095236752) at dl-debug. 3. That said, your stack trace is really strange: _dl_debug_initialize (ldbase=4294967292, ns=1095236752) at dl-debug. Call qRegisterMetaType<std::string> (); in the initialization of your code. qRegisterMetaType vs. See also state() and Creating Custom Qt Types. To start viewing messages, select the forum that you want to visit from the selection below. cpp. The class is used as a helper to marshall types in QVariant and in queued. Call qRegisterMetaType() to make types available to non-template based functions, such as the queued signal and slot connections. In general, you can only export two kinds of C++ types to QML: QObject-derived classes and some build-in value types, see this documentation page. 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. That said, your stack trace is really strange: _dl_debug_initialize (ldbase=4294967292, ns=1095236752) at dl-debug. See the Qt D-Bus Type System page for more information on the type system. 幸哉~ Qt是支持自定义信号，且自定义信号可以发送自定义数据类型的对象。. Any class or struct that has a public default constructor, a public copy constructor, and a. The documentation for exposing C++ properties to QML says that: "Note: Do not use typedef or using for Q_PROPERTY types as these will confuse moc. Also you may need to use qRegisterMetaType function. I want to use my objects as QVariants and for queued connections. It's a bit convoluted to follow, and definitely depends on which Qt modules have been included (the meta type system is designed to be expandable this way -- eg. I pass the MyClass pointer to the streaming operator and only stream things like QString, QPointF, etc. To copy to clipboard, switch view to plain text mode. You can make them known ( Q_DECLARE_METATYPE ), however you can't register them as QML type. Note that you are technically lying to the meta type system. The correct syntax is Q_DECLARE_METATYPE (std::string) without the ;. 4. 该类型必须有公有的 构造、析构、复制构造 函数. To enable creation of objects at run-time, call the qRegisterMetaType() template function to register it with the meta-object system. Using Q_ENUM () allows you to retrieve at run-time the name of an enum value: Q_GADGET makes a class member, staticMetaObject, available. This is not the case, since the following succeeded: @QMetaType::type("MyClass"); // success@. 23k 10 10 gold. Even though we do not intend. cpp. I however have a scenario where I want to declare such an object in qml and transmit it to the c++. Is your Q_DECLARE_METATYPE in a header file or an implementation file? Incidentally, there is a mistake in TreeItem. It is not safe to make a QObject's copy constructor public. Enum has been moved from outside of the class to inside of it. cpp. 1. See the Custom Type Example for code. 1. io Please note that I do not use Q_DECLARE_METATYPE on purpose because I don't actually need its features (QVariant expansion) right now. This macro is used to specialise the template class QMetaTypeId with typename TYPE, in which, a static member function qt_metatype_id () is defined. Then the TYPE ID is saved in local static vairable metatype_id. This function returns the Qt meta type id for the type (the same value that is returned from qRegisterMetaType()). I've registered my class with: @Q_DECLARE_METATYPE(MyClass);@ and. You are looking for the Q_ENUM () macro. So I don't stream the pointer itself just copy the properties and set them to a new created pointer object. e. I am also using some in queued signal and slot connections. Since Qt 5. c:55 This looks like some loader initialization mismatch, check debug vs release builds of your application and libraries that are used. This is by design. View Profile View Forum Posts View Articles Beginner Join Date Nov 2014 Posts 6 Qt products. An alternative would be to wrap shared_ptr<int> in your own class and implement comparison the way you want. To start viewing messages, select the forum that you want to visit from the selection below. [since 6. See also Thread Support in Qt, QObject::connect(), qRegisterMetaType(), and Q_DECLARE_METATYPE(). Call qRegisterMetaType() to register the data type before you establish the connection. qRegisterMetaType is also called in the class constructor. 8. In some cases in Qt 4, it is also necessary to use the qRegisterMetaType method. 0 and have problems registering my own class as a QMetaType. So, whatever Q_DECLARE_METATYPE is doing cannot be done by writing a function call. Adding a Q_DECLARE_METATYPE () makes the type known to all template based functions, including QVariant. QMetaType::type () is a bit slower, but compilation succeeds if a type is not registered. e. Q_DECLARE_METATYPE is required to store type with QVariant, those two are required to register object's "big three" to manage it as resource and its serialization methods. Qt Code: Switch view. qRegisterMetaType vs. . c:55 This looks like some loader initialization mismatch, check debug vs release builds of your application and libraries. When using signals and slots with multiple threads, see Signals and Slots Across Threads. qRegisterMetaType<FileNodePointer> ("FileNodePointer"); should be called once (in main, constructor etc. 4 which does not support all C++11 features. Q_DECLARE_METATYPE QMetaType::type. I just found multiple examples showing the usage of Q_ENUM and Q_ENUMS and looking into the definition of Q_ENUM showed me that it includes Q_ENUMS and other definitions. Note that for enum types, you no not even need to call qRegisterMetaType () in these cases. J 1 Reply Last reply Reply Quote 0. One of these plugins uses Q_DECLARE_METATYPE on some types that need to be stored in a QVariant. # In the class MainWindow declaration #ifndef Q_MOC_RUN # define the tag text as empty,. 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. The class is used as a helper to marshall types in QVariant and in queued signals and slots connections. That would allow you to use. i. One of these plugins uses Q_DECLARE_METATYPE on some types that need to be stored in a QVariant. このケースでも、Q_DECLARE_METATYPE(QSharedPointer<MyObject>)の宣言と、qRegisterMetatype<QSharedPointer<MyObject>>()の呼び出しが必要になる。 上のサンプルでは、同じsignalに対して2回connectを実行している。 The correct syntax is Q_DECLARE_METATYPE (std::string) without the ;. Type is not registered, please use the Q_DECLARE_METATYPE macro to make it known to Qt's meta-object system. JulienMaille @kshegunov last edited by JulienMaille . Last updated at 2016-07-08 Posted at 2015-11-16. g.