该类型必须有公有的 构造、析构、复制构造 函数. akshatrai91 7 Jan 2021, 06:21. Share. I have a few instances of QVector<MyClass> which I want them to be exposed to QScriptEngine. You can make them known ( Q_DECLARE_METATYPE ), however you can't register them as QML type. I think you need to add an explicit export/import directive to the QT_NAMESPACE macro. Q_DECLARE_METATYPE(TYPEDEF) Q_DECLARE_METATYPE(TYPEDEF) mainwindow. Firstly, you shouldn't need to use Q_DECLARE_METATYPE (or qRegisterMetaType) with the enum at all, this is handled by the moc. If you only want to store pointer to Foo with the metatype system, then use qRegisterMetaType<Foo *> ();. Qt has to stay free or it will die. in a header file and call @qRegisterMetaType<std::unique_ptr<Thing>> ();@ before your signal and slots are used. But because QUuid stores its content as a QByteArray which is already supported by QVariant, you. It is meant to be put in a header where the given type is declared. As a workaround, I'm using QVariantMap instead of std::map. Declare new types with Q_DECLARE_METATYPE() to make them available to QVariant and other template-based functions. From the QVariant::value documentation: If the QVariant contains a pointer to a type derived from QObject then T may be any QObject type. 如果是指针类型他需要有完整的定义。使用Q_DECLARE_OPAQUE_POINTER()去注册指针用于转发数据类型。 使用Q_DECLARE_METATYPE()可以让这个数据类型T放到QVariant里面。如果想以队列的方式让T使用信号与槽，当第一次连接的时候就要调用qRegisterMetaType<T>()。Detailed Description. Labels: meta system, Meta type, qt. QMetaType. That said, your stack trace is really strange: _dl_debug_initialize (ldbase=4294967292, ns=1095236752) at dl-debug. I want to use drag-and-drop to drag a QTreeWidgetItem that has std::shared_ptr user data. Also Q_DECLARE_METATYPE does not register a type, but declares it. 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. The Q_DECLARE_METATYPE() macro and qRegisterMetaType() function documentation contain more detailed information about their uses and limitations. Macros Detailed Description The QMetaType class manages named types in the meta-object system. Research The QMetaType class manages named types in the meta-object system. You may have to register before you can post: click the register link above to proceed. 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",. qRegisterMetaType vs. As you have already found out, you must use Q_DECLARE_METATYPE to make the type known to Qt. Unsure if my idea would work, I created a DataPoint class marked with Q_GADGET with three properties defined using Q_PROPERTY. Declare new types with Q_DECLARE_METATYPE() to make them available to QVariant and other template-based functions. 12. Adding a Q_DECLARE_METATYPE() makes the type known to all template based functions, including QVariant. 1. 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. Also Q_DECLARE_METATYPE does not register a type, but declares it. I have added Q_DECLARE_METATYPE(quint32) in Class2. Using the macro directly turned out to be impossible. 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. It was also no big issue to call qRegisterMetaType () automatically. See the Qt D-Bus Type System page for more information on the type system. wysota. Also, Q_DECLARE_METATYPE(MyNamespace::MyType) should be in the header declaring MyType so that you don't have to repeat it all over again and again. By the way, Qt 4. This is not the case, since the following succeeded: @QMetaType::type("MyClass"); // success@. Our first stop for registrations always is the macro Q_DECLARE_METATYPE. template <typename T> struct QMetaTypeId<Container<T>>. ) summary refs log tree commit diff stats Foo and Foo* are different types and need to be registered separately. The QMetaType class manages named types in the meta-object system. Similarly you can create a mutable view of type QAssociativeIterable on any container registered with Q_DECLARE_ASSOCIATIVE_CONTAINER_METATYPE(). cruz Hello, To be completely candid, I haven't used GDB remotely and I'm certainly not so intimate with it for the log to speak to me much. [quote author="Andre" date="1306394817"]In that case, I think you need to register them. The same plugin may be loaded multiple times during the application's lifetime. . It will return the same result if it was called before. namespace CCS { Q_DECL_EXPORT Q_NAMESPACE. The macro will register your variable with the Qt Meta-Object System, which will allow you to. 11. " Yet types like QVariantMap are themself typedefs. Any class or struct that has a public default constructor, a public copy. no unexpected garbage. c:55 This looks like some loader initialization mismatch, check debug vs release builds of your application and libraries. See also Thread Support in Qt, QObject::connect(), qRegisterMetaType(), and Q_DECLARE_METATYPE(). To make the custom type. cpp. However, as you need the type to be. An alternative would be to wrap shared_ptr<int> in your own class and implement comparison the way you want. 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. I'm confused by this error, as the documentation states (emphasis mine): Returns the meta type id of type T at compile time. It associates a type name to a type so that it can be created and destructed dynamically at run-time. Also, this Q_DECLARE_METATYPE(SharedTestClass) shouldn't be needed. So I am doing this: Qt Code: Switch view. If the type was not declared with Q_DECLARE_METATYPE (), compilation will fail. // But the split allows to. uint64; If this is your first visit, be sure to check out the FAQ by clicking the link above. Call qRegisterMetaType() to make types available to non-template based functions, such as the queued signal and slot connections. w/out GUI module you wouldn't have any of those types available). 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. The other overload around has almost the same form but for the. // to be declared somewhere Q_DECLARE_METATYPE(std::string); // to be invoked at the beginning of program qRegisterMetaType<std::string>(); Without type registration Qt doesn't know how to do. QLocalSocket::SocketState is not a registered metatype, so for queued connections, you will have to register it with Q_DECLARE_METATYPE() and qRegisterMetaType(). But with the shared_ptr object, not a pointer to the shared pointer! You will have to register std::shared_ptr<yourclass> with the Qt meta object system before this can work, i. 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. The following should work: Note that you also have to call qRegisterMetaType<MyMpiMessage> (); before you use the function the first time. jsulm Lifetime Qt Champion @shivaVMC last edited by . 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. I have an application that requires use of both Qt 3D and the QCustomPlot library. 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. void QLocalSocket:: abort ()The Qt docs make it clear that to use a custom type with Queued Connections, I need to use both Q_DECLARE_METATYPE and qRegisterMetaType. Note that you are technically lying to the meta type system. (Make sure 'QVector<int>' is. [override virtual] bool QAbstractSocket:: waitForBytesWritten (int msecs = 30000) Reimplements:. You can register a class pointer as the metatype, though. 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. 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. Of course it's a bug and an odd mistake that Q_DECLARE_METATYPE(QList<QSslError>) is in qsslsocket. Qt is throwing an exception because it doesn't know how to store the shared_ptr onto a QDataStream. . @SGaist Yes, I am using it with QVariant, mostly with QSettings to save and retrieve data easily by overriding QDataStream operators. J 1 Reply Last reply Reply Quote 0. type() typeName() PySide6. This function was introduced in Qt 5. 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. From the docs: int qRegisterMetaType ( const char * typeName ) Registers the type name typeName to the type T. 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的qRegisterMetaType函数: unregisterType(const char *typeName) 函数的作用是取消自己先前注册的某个metatype类型。That is sad. Greetings. 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. The QMetaType class manages named types in the meta-object system. Adding a Q_DECLARE_METATYPE() makes the type known to all template based functions, including QVariant. 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. // - in a header: // - define a specialization of this template calling an out-of. cpp. There's also no need for that typedef, it only makes the code less readable. Enum has been moved from outside of the class to inside of it. qt. 2、在类型定义完成后，加入声明：Q_DECLARE_METATYPE (MyDataType); 3、在main ()函数中. 4. When these files are processed by repc, repc generates both Source and Replica header files. @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. Share Improve this answer Follow answered Jul 23, 2014 at 15:37. QVariantList MyClass::getFooCollection (void) const { QVariantList list; for (const auto& l: fooCollection_) { list. To start viewing messages, select the forum that you want to visit from the selection below. In the header, after the class declaration, outside the namespace, I've included. qRegisterMetaType vs. The class is used as a helper to marshall types in QVariant and in queued signals and slots connections. Declare new types with Q_DECLARE_METATYPE () to make them available to QVariant and other template. Share. Custom Type Qlist and Scope. uint64; If this is your first visit, be sure to check out the FAQ by clicking the link above. 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. The fix is probably to include qsslsocket. c:55 This looks like some loader initialization mismatch, check debug vs release builds of your application and libraries. Call qRegisterMetaType() to make types available to non-template based functions, such as the queued signal and slot connections. qRegisterMetaType() requires also a Q_DECLARE_METATYPE() – dtech. Consider the specific case of qRegisterMetaType. Declare new types with Q_DECLARE_METATYPE () to make them available. SocketState is not a registered metatype, so for queued connections, you will have to register it with Q_DECLARE_METATYPE() and qRegisterMetaType(). I meet a qt metatype issue. Declare new types with Q_DECLARE_METATYPE () to make them available. Inheritance diagram of PySide6. uint64; If this is your first visit, be sure to check out the FAQ by clicking the link above. Connect and share knowledge within a single location that is structured and easy to search. Using Q_ENUM () allows you to retrieve at run-time the name of an enum value: Q_GADGET makes a class member, staticMetaObject, available. 1. This function is useful to register typedefs so they can be used by QMetaProperty, or in QueuedConnections. waitForConnected ([msecs=30000]) # Parameters: msecs – int. I need to call the Q_DECLARE_METATYPE() to pass the smart pointer. This allows me to use this type in a Q_PROPERTY, this all. You may have to register before you can post: click the register link above to proceed. It does not say anything about registering the type. If you are using queued connections, you need to register std::string as meta type. QObject can't be copied and all its descendants can't be copied also. Also, this Q_DECLARE_METATYPE(SharedTestClass) shouldn't be needed. call qRegisterMetaType with the name specified, else reading properties. The. Q_DECLARE_METATYPE(MyStruct) Q_DECLARE_METATYPE(MyList) QDBusArgument &operator<<(QDBusArgument &, const MyStruct&);. qRegisterMetaType() docs say: Any class or struct that has a public constructor, a public copy constructor, and a public destructor can be registered. 1 Answer. 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. As a workaround you can call the Q_DECLARE_METATYPE macro from the implementation files that need it instead of calling it from the header files, or as the documentation suggests, call it from private headers in each library. Note that you are technically lying to the meta type system. Read and abide by the Qt Code of Conduct. cpp 中，用connect函数 将抛出此结构体的信号和接收此结构体的槽函数关联之前，要调用qRegisterMetaType. It seems that for a metatype that is a QList<MyClass::MyEnum> I must. This requires the exchanged data to be of a type that is recognizable by the engine. [virtual] QAbstractSocket:: ~QAbstractSocket Destroys the socket. Q_DECLARE_METATYPE (std::string) Quoting Qt Doc. G. qRegisterMetaType is also called in the class constructor. What is(are) the good place(s) to put the qRegisterMetaType call? I obviously don't want any expllicit. . staticMetaObject is of type QMetaObject and provides access to the enums declared with Q_ENUMS. Type is not registered, please use the Q_DECLARE_METATYPE macro to make it known to Qt's meta-object system. Similarly you can create a mutable view of type QAssociativeIterable on any container registered with Q_DECLARE_ASSOCIATIVE_CONTAINER_METATYPE(). This function was introduced in Qt 4. So, you don't want 'Widget' to be a metatype, you want 'Widget*' to be a metatype so that you can put a Widget* in a QVariant for example. See also state() and Creating Custom Qt Types. The struct is declared in my worker class, which is inside a namespace. So my first idea:. Note: it's also safe to call qRegisterMetaType () multiple times. Registered enumerations are automatically registered also to the Qt meta type system, making them known to QMetaType without the need to use. QMetaType::type () returns the same ID as qMetaTypeId (), but does a lookup at runtime based on the name of the type. 0. Avoid having to qRegisterMetaType (pointer vs reference), concern about const. It is only useful to the code that follows it, in the same file. on top of main. QtNetwork. Now you have a valid QObject. QList<T> isn't really a pre-defined variant type (except QList<QVariant>) so it technically resolves to a QMetaType::UserType. 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。. // This primary template calls the -Implementation, like all other specialisations should. To register VideoMeta you need to call qRegisterMetaType<VideoMeta>(). Sorted by: 1. the type name must be specified without the class, as in. since it is a runtime registration. This allows us to use the Enum as a custom-type of a QVariant, to pass it between QML and Qt, to use it in synchronous signal-slot connections, and to print the symbolic enums (instead of a magic number) with qDebug(). With Q_DECLARE_METATYPE and without qRegisterMetaType: No warning, slot is called With Q_DECLARE_METATYPE and with qRegisterMetaType: No warning, slot is called. I want to use my objects as QVariants and for queued connections. It associates a type name to a type so that it can be created and destructed dynamically at run-time. Than I did read this copy constructor of derived QT class and the answer by BЈовић. By convention, these files are given a . Step 1 (mark for MOC), build some QObjects That pattern uses Q_PROPERTY and Q_OBJECT and the MoC tool. call qRegisterMetaType() to register the data type before you establish the connection. By convention, these files are given a . Declare new types with Q_DECLARE_METATYPE () to make them available to QVariant and other template-based functions. 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ある。Trying to register std::map<non_template_type_1,non_template_type_2> with Q_DECLARE_METATYPE() results in compilation failure and apparently is not supported. QLocalSocket. View Profile View Forum Posts View Articles Beginner Join Date Nov 2014 Posts 6 Qt products. hpp which is included in Class1. But I can't see a method to insert myClass into. QMetaType registerNormalizedTypedef normalizedTypeName, type: metaType ); return. Avoid having to qRegisterMetaType (pointer. As G. That's probably there, as qRegisterMetaType () wouldn't compile otherwise. J. Creating and Destroying Custom Objects 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 class. I created a. 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. ompiler (repc) generates header files based on an API definition file. qRegisterMetaType vs. You can't with Q_GADGETS. What worries me is that. QMetaType registerNormalizedTypedef normalizedTypeName, type: metaType ); return. See also state(). Read and abide by the Qt Code of Conduct. c:55 This looks like some loader initialization mismatch, check debug vs release builds of your application and libraries that are used. 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:. Enumerations that are declared with Q_ENUM have their QMetaEnum registered in the enclosing QMetaObject. To call qRegisterMetaType (), you still need to use Q_DECLARE_METATYPE (). Detailed Description. This version of the function is to register alias types. Step 1 (mark for MOC), build some QObjects That pattern uses Q_PROPERTY and Q_OBJECT and the MoC tool. The class is used to send arguments over D-Bus to remote applications and to receive them back. So I don't stream the pointer itself just copy the properties and set them to a new created pointer object. . In my own code, I use Q_DECLARE_METATYPE for classes I want to store. 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. @SGaist Yes, I am using it with QVariant, mostly with QSettings to save and retrieve data easily by overriding QDataStream operators. struct Matrix { double data [4] [4]; }; Ideally you should be using eigen3. 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. {. x however, the code generated by moc will call qRegisterMetaType for you if moc can determine that the type may be registered as a. The class is used as a helper to marshall types in QVariant and in queued signals and slots connections. 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. 12. You can also use QMetaEnum::fromType() to get the QMetaEnum. This also makes the type available for queued. There's also no need for that typedef, it only makes the code less readable. I also added qRegisterMetaType<DataPoint> () to the initialisation method of my main. The logical equivalent of a const T &r (reference to const T) is a const T * const p (const pointer to const T). Update. Returns true if convert can convert from fromType to toType. EDIT: When you convert your class to QVariant it uses a. h instead ofQVariant x2; x2. This worked very well. your custom type definition. by using qRegisterMetaType(). Type is not registered, please use the Q_DECLARE_METATYPE macro to make it known to Qt's meta-object system. I need to call the Q_DECLARE_METATYPE() to pass the smart pointer. There's no need to call qRegisterMetaType that many times, once is enough. As a workaround, I'm using QVariantMap instead of std::map. It associates a type name to a type so that it can be created and destructed dynamically at run-time. 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. If you ever wondered what does Q_DECLARE_META_TYPE or qRegisterMetaType do and when to use (or not to use) them, read on. 2. 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. cpp. c:55 This looks like some loader initialization mismatch, check debug vs release builds of your application and libraries that are used. 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. Also, this Q_DECLARE_METATYPE(SharedTestClass) shouldn't be needed. You have to register your class to Qt meta objects system. 11. Compares this QVariant with v and returns true if they are equal;. The reasoning is found in the. 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); This now makes it possible for Message values to be stored in QVariant objects and retrieved later. 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. So in your case you need to declare. To use the type T in queued signal and slot connections,. . We all have started by asking questions. Returns the internal ID used by QMetaType. Does your code ever call qRegisterMetatype() or use Q_DECLARE_METATYPE()? 10th November 2014, 06:23 #3. Adding a Q_DECLARE_METATYPE() makes the type known to all template based functions, including QVariant. I'm using Qt 5. 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. QList<AnotherObject*> has of course been registered with Q_DECLARE_METATYPE and qRegisterMetaType(). Per Qt documentation: To use the type T in QVariant, using Q_DECLARE_METATYPE () is sufficient. To start viewing messages, select the forum that you want to visit from the selection below. When I emit a signal, then I get next error to the output stream:. To start viewing messages, select the forum that you want to visit from the selection below. Although I'm. Q_DECLARE_METATYPE. To start viewing messages, select the forum that you want to visit from the selection below. In short, I get following error: QObject::connect: Cannot queue arguments of type 'cv::Mat' (Make sure 'cv::Mat' is registered using qRegisterMetaType (). 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. ) QObject::connect: Cannot queue arguments of type 'QVector<int>'. container. The class is used as a helper to marshall types in QVariant and in queued. In the example's Message class, a static method is included to do this. The class is used as a helper to marshall types in QVariant and in queued signals and slots connections. 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. There's also no need for that typedef, it only makes the code less readable. Is your Q_DECLARE_METATYPE in a header file or an implementation file? Incidentally, there is a mistake in TreeItem. 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. I'm trying to use custom classes in QAbstractListModel, and the Q_DECLARE_METATYPE doesn't work at all! To test where the problem is, I've simplified the code as the following: #include <QMetaType> #include <QVariant> #include <QDebug> typedef int x; Q_DECLARE_METATYPE (x) void main () { QVariant v; qDebug () <<. Q_DECLARE_METATYPE(shared_ptr<SomeClass> const &) qRegisterMetaType<shared_ptr<SomeClass> const&>(); 许多标准API都有 QString const & ，因此我认为从根本上来说是可能的，而我只是想不出语法。You actually need to do it once (i. no unexpected garbage. JulienMaille @kshegunov last edited by JulienMaille . QMetaType::type () is a bit slower, but compilation succeeds if a type is not registered. Also, this Q_DECLARE_METATYPE(SharedTestClass) shouldn't be needed. Thanks for the suggestion. QVariant x2 = QVariant::fromValue( x1); To copy to clipboard, switch view to plain text mode. It associates a type name to a type so that it can be created and destructed dynamically at run-time. See also disconnect(), sender(), qRegisterMetaType(), Q_DECLARE_METATYPE(), and Differences between String-Based and. 1. QVariant v = QVariant::fromValue<cMyClass>(MyObject); However, as soon as I use Q_DECLARE_METATYPE, I get errors about using a deleted function. QAbstractSocket::SocketState is not a registered metatype, so for queued connections, you will have to register it with Q_REGISTER_METATYPE() and qRegisterMetaType(). However, I cannot figure out how to verify that the included parameter is FACE_UP or FACE_DOWN. 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. Q_DECLARE_METATYPE accepts objects with public constructor, copy constructor and destructor. The Custom Type and Queued Custom Type examples show how to implement a custom type with the features outlined in this document. Read and abide by the Qt Code of Conduct. qRegisterMetaType vs. uint64; If this is your first visit, be sure to check out the FAQ by clicking the link above. 1 Answer. As said in int qRegisterMetaType () documentation: To use the type T in QVariant, using Q_DECLARE_METATYPE () is sufficient. 6. Q_DECLARE_METATYPE(TYPEDEF) Q_DECLARE_METATYPE(TYPEDEF) mainwindow. :) QApplication is the root QObject of the program and its full initialization is required before anything can practically be done with anything else. Q_DECLARE_METATYPE QMetaType::type. Thus you need to use the runtime check QMetaType::type (). 0. The default access for a class is private, so that Container* data();. 3 Answers Sorted by: 13 "qRegisterMetaType" is a function. Q_DECLARE_METATYPE. Assuming base and derived are Q_GADGETs you want to get a static member. 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. Any class or struct that has a public default constructor, a public copy. This example is meant to declare and register only the pointer type of a given class: In conclusion: Don't use Q_DECLARE_METATYPE and qRegisterMetaType for your QObject enum. Declare new types with Q_DECLARE_METATYPE() to make them available to QVariant and other template-based functions. To use the type T in queued signal and slot connections, qRegisterMetaType () must be called before the first connection is established. rep file extension, short for Replica. 该类型必须有公有的 构造、析构、复制构造 函数. 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. void QAbstractSocket:: abort ()2 Answers. @Daddedebad As @Bonnie says qRegisterMetaType. ", which suggests it is only for classes and structs. 1、自定MyDataType 类型，在这个类型的顶部包含：#include <QMetaType>. Sorted by: 3. Registers the type name . c:55 This looks like some loader initialization mismatch, check debug vs release builds of your application and libraries.