Q_DECLARE_METATYPE(MyClass*); That's how Qt handles it with QObject and QWidget. 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. e. Jun 13, 2021 at 19:37. Accessing an enum stored in a 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. QtCore. The code compiles and runs ok. This object can then be passed from QML to C++ via Q_INVOKABLE. There's no need to call qRegisterMetaType that many times, once is enough. 12. So my first idea:. 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. This fixed the issue. My workround was to explicitly cast the enum values to int when passing them onto a function requiring a QVariant type, in my case when adding a QComboBox item, and then casting it back to my enum class type at value retrieval. Note: it's also safe to call qRegisterMetaType () multiple times. 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. Specifically, the function have to be called before using the struct. Q_DECLARE_METATYPE. Read and abide by the Qt Code of Conduct. Normally, you would only register the pointer form if your class cannot be copied, as in the case of QObject and derivatives, but. qRegisterMetaType usage. Qt Base (Core, Gui, Widgets, Network,. The reasoning is found in the. To start viewing messages, select the forum that you want to visit from the selection below. That would allow you to use. To start viewing messages, select the forum that you want to visit from the selection below. 【2】使用方法（声明 和 注册自定义数据类型）. Enum has been moved from outside of the class to inside of it. From the docs: int qRegisterMetaType ( const char * typeName ) Registers the type name typeName to the type T. 0. See also state() and Creating Custom Qt Types. Last updated at 2016-07-08 Posted at 2015-11-16. The following should work: Note that you also have to call qRegisterMetaType<MyMpiMessage> (); before you use the function the first time. Research The QMetaType class manages named types in the meta-object system. 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. 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. See also state(). The following code will work as well: using namespace foo; Q_DECLARE_METATYPE (MyClass) Teams. struct StandardData { int EmpId; QString Name; }; Q_DECLARE_METATYPE (StandardData) Additionally, you might need to call qRegisterMetaType. Q_DECLARE_METATYPE(MyClass); qRegisterMetaType<MyClass>(); I can use the type in queued connection with signals like this one: void MySignal(MyType o); Now I also would like to use the type with signals like this: void MyVectorSignal(QVector<MyType> v);Qt 5. 6. This macro is used to specialise the template class QMetaTypeId with typename TYPE, in which, a static member function qt_metatype_id () is defined. statement to the header file containing. I guess it's the qRegisterMetaType () call itself that's missing. See also. [quote author="Andre" date="1306394817"]In that case, I think you need to register them. Hope it. Obviously then you would not do registerComparator (). Now I want to read this property with Qt's meta object system. Good workaround: you may register your type with Q_DECLARE_METATYPE ( IBase * ) macro and wrap your. I however have a scenario where I want to declare such an object in qml and transmit it to the c++. cpp. Call qRegisterMetaType() to make types available to non-template based functions, such as the queued signal and slot connections. h. Qt Code: Switch view. Learn more about Teams Declaring a meta type. 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. That said, your stack trace is really strange: _dl_debug_initialize (ldbase=4294967292, ns=1095236752) at dl-debug. Then you should register your object to use it with QML. 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. Declare new types with Q_DECLARE_METATYPE () to make them available to. To start viewing messages, select the forum that you want to visit from the selection below. Additionally Qt5 always refers to Q_DECLARE_METATYPE, saying that qRegisterMetaType is only when you want to. Teams. Execute qRegisterMetaType<QItemSelection> (); before it is used as such, e. In short, I get following error: QObject::connect: Cannot queue arguments of type 'cv::Mat' (Make sure 'cv::Mat' is registered using qRegisterMetaType (). QML_DECLARE_TYPE. 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. This function returns the Qt meta type id for the type (the same value that is returned from qRegisterMetaType()). Inheritance diagram of PySide6. in your main function or in the constructor of AudioGuiApplication. But this is all useless if you are not using templates. Here you can see that the macro expands to nothing. You may have to register before you can post: click the register link above to proceed. 1 Answer. 2. Q_DECLARE_METATYPE(MyObject*) somewhere in your code. From the QVariant::value documentation: If the QVariant contains a pointer to a type derived from QObject then T may be any QObject type. QML Qvariant from custom class. 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. 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. so that was all, but remember to use Q_DECLARE_METATYPE, qRegisterMetaType macros for registering your custom type with Qt meta object system. nyaruko. by using qRegisterMetaType(). The class is used to send arguments over D-Bus to remote applications and to receive them back. 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. QAbstractSocket::SocketState is not a registered metatype, so for queued connections, you will have to register it with Q_DECLARE_METATYPE() and qRegisterMetaType(). cpp. I think you need to add an explicit export/import directive to the QT_NAMESPACE macro. Q_DECLARE_METATYPE accepts objects with public constructor, copy constructor and destructor. {. 0. 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. Since Qt 5. In my own code, I use Q_DECLARE_METATYPE for classes I want to store. // 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. 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 read a bit and it seems that Q_DECLARE_SMART_POINTER_METATYPE is supposed to allow this to work. Then you should register your object to use it with QML. Q_DECLARE_META_TYPE (Fruit) and qRegisterMetaType were redundant: #define PluginInterface_iid "pluginInterface" Q_DECLARE_INTERFACE (PluginInterface, PluginInterface_iid) //Actual plugin implementing PluginInterface class. c:55 This looks like some loader initialization mismatch, check debug vs release builds of your application and libraries. See also state() and Creating Custom Qt Types. 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. 5 is compiled with GCC 4. But I really would like to know the correct way to solve this problem; one where it is not possible to modify. The default access for a class is private, so that Container* data();. 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 QObject { Q_OBJECT public. 2. This replaces the now-deprecated Q_ENUMS and will automatically register the metatype. Returns the internal ID used by QMetaType. That's created by this macro. The class is used as a helper to marshall types in QVariant and in queued signals and slots connections. 1、自定MyDataType 类型，在这个类型的顶部包含：#include <QMetaType>. Note that you are technically lying to the meta type system. So I tried declaring the following at end of my worker thread class Q_DECLARE_METATYPE(cv::Mat);. I simplified the code quite a bit and the problem went away. The. You may have to register before you can post: click the register link above to proceed. 1. Then the TYPE ID is saved in local static vairable metatype_id. After googling this, I found this correspondence, which was only available through a third party archival site as google. Believing an Question from 2010 and the Qt Documentation, the operator==() doesn't work with custom types. You may have to register before you can post: click the register link above to proceed. That's created by this macro. To start viewing messages, select the forum that you want to visit from the selection below. 基本理解. I believe this is related to the fact that. So I am doing this: Qt Code: Switch view. 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. [virtual] QAbstractSocket:: ~QAbstractSocket Destroys the socket. Call qRegisterMetaType() to make type available to non-template based functions, such as the queued signal and slot connections. The "traditional" way of doing this is to convert each element to a QVariant, and pass collection as a QVariantList. Basically, I created a library containing a type: struct MyCustomType {. Type is not registered, please use the Q_DECLARE_METATYPE macro to make it known to Qt's meta-object system. qRegisterMetaType vs. To use the type T in QVariant, using Q_DECLARE_METATYPE() is sufficient. It associates a type name to a type so that it can be created and destructed dynamically at run-time. QMetaType::type () is a bit slower, but compilation succeeds if a type is not registered. staticMetaObject is of type QMetaObject and provides access to the enums declared with Q_ENUMS. genC last edited by . no unexpected garbage data or the like). You should use Q_DECLARE_METATYPE macro for this. You can't with Q_GADGETS. I think you need to add an explicit export/import directive to the QT_NAMESPACE macro. Declare new types with Q_DECLARE_METATYPE () to make them available to QVariant and other template-based functions. 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 read a bit and it seems that Q_DECLARE_SMART_POINTER_METATYPE is supposed to allow this to work. private: AnotherQGadgetClass test_; } Q_DECLARE_METATYPE(QGadgetClass) I am trying to access Q_GADGET from QML classic way like accessing a Q_OBJECT , but the setters are not called. To start viewing messages, select the forum that you want to visit from the selection below. You may have to register before you can post: click the register link above to proceed. But I couldn't register the type because it's a QObject and I don't have access to the implementation to change it. Q_GADGET makes a class member, staticMetaObject, available. What is(are) the good place(s) to put the qRegisterMetaType call? I obviously don't want any expllicit. To enable using the type in queued signals and such, there also needs to be a corresponding call: qRegisterMetaType<foo::FooState>(); Question. I have registered an enumeration type "ClefType" within my header file - this enum is registered with the MetaObject system using the Q_DECLARE_METATYPE and Q_ENUMS macros. 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. Custom Type Qlist and Scope. 基本理解. Qt. Q_DECLARE_METATYPE, as pointed out by @SingerOfTheFall, would register template based type into QVariant (so it can be retrieved using qvariant_cast<T>()). Than I did read this copy constructor of derived QT class and the answer by BЈовић. g. // - in a header: // - define a specialization of this template calling an out-of. QAbstractSocket::SocketState is not a registered metatype, so for queued connections, you will have to register it with Q_DECLARE_METATYPE() and qRegisterMetaType(). 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. You can register a class pointer as the metatype, though. 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. There's also no need for that typedef, it only makes the code less readable. Also you may need to use qRegisterMetaType function. . Our first stop for registrations always is the macro Q_DECLARE_METATYPE. 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. Declare new types with Q_DECLARE_METATYPE() to make them available to QVariant and other template-based functions. 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. 4 which does not support all C++11 features. It is not safe to make a QObject's copy constructor public. To use the type T in queued signal and slot connections, qRegisterMetaType<T>() must be called before the first connection is established. qRegisterMetaType you'll need if creating objects by class name dynamically, and it seems for queued connections,. One of these plugins uses Q_DECLARE_METATYPE on some types that need to be stored in a QVariant. I explicitly don't want to update it on every change to one of the quantities, so they don't. This worked very well. Q_DECLARE_METATYPE与qRegisterMetaType学习. Registers the type name . In short, I get following error: QObject::connect: Cannot queue arguments of type 'cv::Mat' (Make sure 'cv::Mat' is registered using qRegisterMetaType (). Adding a Q_DECLARE_METATYPE() makes the type known to all template based functions, including QVariant. Q_DECLARE_METATYPE(MyStruct) Q_DECLARE_METATYPE(MyList) QDBusArgument &operator<<(QDBusArgument &, const MyStruct&);. Update. Re: Qt warning of type conversion already registered Originally. Call qRegisterMetaType() to make types available to non-template based functions, such as the queued signal and slot connections. ) I got the hint "expected a declaration" when I tried to use qRegisterMetaType from the global scope in my cpp file. Thus you need to use the runtime check QMetaType::type (). Unsure if my idea would work, I created a DataPoint class marked with Q_GADGET with three properties defined using Q_PROPERTY. Re: Qt warning of type conversion already registered Originally. . The class is used as a helper to marshall types in QVariant and in queued signals and slots connections. @SGaist Yes, I am using it with QVariant, mostly with QSettings to save and retrieve data easily by overriding QDataStream operators. 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. due to requirements at my job, I had to revert by build from Qt5. The file (called a "rep" file) uses a specific (text) syntax to describe the API. Share. QList<AnotherObject*> has of course been registered with Q_DECLARE_METATYPE and qRegisterMetaType(). c:55 This looks like some loader initialization mismatch, check debug vs release builds of your application and libraries that are used. 1. The default access for a class is private, so that Container* data(); declares a private member function, but it looks like you expect it to be public. To use the type T in QVariant, using Q_DECLARE_METATYPE() is sufficient. // But the split allows to. When using signals and slots with multiple threads, see Signals and Slots Across Threads. The class in Qt responsible for custom types is QMetaType . If the pointer stored in the QVariant can be qobject_cast to T, then that result is returned. See also state(). . 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. Declare new types with Q_DECLARE_METATYPE () to make them available to QVariant and other template. Similarly you can create a mutable view of type QAssociativeIterable on any container registered with Q_DECLARE_ASSOCIATIVE_CONTAINER_METATYPE(). 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. namespace CCS { Q_DECL_EXPORT Q_NAMESPACE. To use the type T in queued signal and slot connections, qRegisterMetaType<T>() must be called before the first connection is established. QObject::connect: Cannot queue arguments of type 'MyStruct'. g. The file (called a "rep" file) uses a specific (text) syntax to describe the API. Re: How to use Q_DECLARE_METATYPE. Also, to use type T with the QObject::property () API, qRegisterMetaType () must be. To start viewing messages, select the forum that you want to visit from the selection below. i. I'm confused by this error, as the documentation states (emphasis mine): Returns the meta type id of type T at compile time. You pass around pointers instead. 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(). " Currently I have no UI implemented (yet!). 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. Call qRegisterMetaType () to make types available to non-template based functions, such as the queued signal and slot connections. 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(). See also state() and Creating Custom Qt Types. You should use Q_DECLARE_METATYPE macro for this. call qRegisterMetaType with the name specified, else reading properties. 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。. I created a. See full list on doc. c:55 This looks like some loader initialization mismatch, check debug vs release builds of your application and libraries that are used. It must appear in a code block. 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. Declare new types with Q_DECLARE_METATYPE () to make them available to. h) of the derived class. There's no such thing as a "const reference" because references are always const -- you can't reseat them. Any class or struct that has a public constructor, a public copy constructor, and a public destructor can be registered. 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. Q&A for work. QDBusArgument is the central class in the Qt D-Bus type. c:55 This looks like some loader initialization mismatch, check debug vs release builds of your application and libraries that are used. Use Q_DECLARE_METATYPE (std::string) in one of your headers. That's probably there, as qRegisterMetaType () wouldn't compile otherwise. qRegisterMetaType<FileNodePointer> ("FileNodePointer"); should be called once (in main, constructor etc. 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. Q_DECLARE_METATYPE(TYPEDEF) Q_DECLARE_METATYPE(TYPEDEF) mainwindow. Situation. To start viewing messages, select the forum that you want to visit from the selection below. I've registered my class with: @Q_DECLARE_METATYPE(MyClass);@ and. See also disconnect(), sender(), qRegisterMetaType(), Q_DECLARE_METATYPE(), and Differences between String-Based and. 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 am also using some in queued signal and slot connections. See also state() and Creating Custom Qt Types. (Make sure 'QVector<int>' is. 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. 4] QString QWebSocket:: subprotocol const. 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. But because QUuid stores its content as a QByteArray which is already supported by QVariant, you. [edit] forgot to mention that you also have to use a worker object. e. [virtual] QLocalSocket:: ~QLocalSocket Destroys the socket, closing the connection if necessary. This results in access violations when Qt. 4 which does not support all C++11 features. "Custom types used by properties need to be registered using the Q_DECLARE_METATYPE() macro so that their values can be stored in QVariant objects. Declare new types with Q_DECLARE_METATYPE () to make them available to QVariant and other template. 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. If the type was not declared with Q_DECLARE_METATYPE (), compilation will fail. You may have to register before you can post: click the register link above to proceed. It is a static method, it does not (cannot) change x2. To register VideoMeta you need to call qRegisterMetaType<VideoMeta>(). qRegisterMetaType vs. 2、在类型定义完成后，加入声明：Q_DECLARE_METATYPE (MyDataType); 3、在main ()函数中. 1. This also makes the type available for queued. multithreaded software and I am getting the warning says: (Make sure 'QVector<int>' is registered using qRegisterMetaType (). So I am doing this: Qt Code: Switch view. I haven't used that module yet but one thing you should do is remove the string argument from your qRegisterMetaType calls. QVariantList MyClass::getFooCollection (void) const { QVariantList list; for (const auto& l: fooCollection_) { list. The ENUM type. 14. You could also Q_DECLARE_METATYPE to register your custom type and then use qMetaTypeId() to get the metaType id. Q_DECLARE_METATYPE. 12. There's no need to call qRegisterMetaType that many times, once is enough. In my module tests, I turn the card up and down, and can verify that the number of signals are increasing using QSignalSpy. The correct syntax is Q_DECLARE_METATYPE (std::string) without the ;. If such a connection is made, and a signal triggered, the runtime warning will be shown: QObject::connect: Cannot. qRegisterMetaType<signed long long>() - do nothing. 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. There's no compile time error, but when I run. Is your feature request related to a problem? No, it's an improvement Please describe. However, it does appear (at least to me) that you're trying to debug a release build of the application. @Wieland Thanks. 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。. To call qRegisterMetaType (), you still need to use Q_DECLARE_METATYPE (). Obviously, a call to qRegisterMetaType<T>(. Any class or struct that has a public default constructor, a public copy. Call qRegisterMetaType<std::string> (); in the initialization of your code. –To copy to clipboard, switch view to plain text mode. 1. 如果非QMetaType内置类型要. Share Improve this answer Follow answered Jul 23, 2014 at 15:37. Here’s the list of what changed: QVariant used to forward isNull () calls to its contained type – but only for a limited set of Qt’s own types. This is by design. Ah, sorry, I didn't noticed that part. That said, your stack trace is really strange: _dl_debug_initialize (ldbase=4294967292, ns=1095236752) at dl-debug. 1 Answer. Share. 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. E. I think it would be great if we could run requests in a QThread, but right now it's not possible because the r. Q_DECLARE_METATYPE. akshatrai91 7 Jan 2021, 06:21. Remember that Q_DECLARE_METATYPE merely defines a specialization of QMetaTypeId for your type. const EventExport& in signal and slot profiles; Sending empty EventExport in prepareExport() so emit has no/low data amount; Checking connect statement (always returns true) Having qDebug() in prepareExport() and signal always appears to be emitted; Calling emit right. Detailed Description. 0. To make the custom. Also, this Q_DECLARE_METATYPE(SharedTestClass) shouldn't be needed. Returns the internal ID used by QMetaType. Qt is throwing an exception because it doesn't know how to store the shared_ptr onto a QDataStream. If I get AnotherQGadgetClass via getter and change it's properties, the setters are called and. As said in int qRegisterMetaType () documentation: To use the type T in QVariant, using Q_DECLARE_METATYPE () is sufficient. 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. 2）添加声明：利用宏 Q_DECLARE_METATYPE. See QMetaType docs for more information. c:55 This looks like some loader initialization mismatch, check debug vs release builds of your application and libraries. There's no compile time error, but when I run. qRegisterMetaType is also called in the class constructor. ) I have defined MyStruct in an accessible header file: myheader. Do do you register the meta type with the call qRegisterMetaType("your custom meta type")? 1 Reply Last reply Reply Quote 0. For those who follow. in a header file and call @qRegisterMetaType<std::unique_ptr<Thing>> ();@ before your signal and slots are used. 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. jsulm Lifetime Qt Champion @shivaVMC last edited by . By convention, these files are given a . Q_DECLARE_METATYPE. ) summary refs log tree commit diff stats Foo and Foo* are different types and need to be registered separately. An alternative would be to wrap shared_ptr<int> in your own class and implement comparison the way you want. Adding a Q_DECLARE_METATYPE() makes the type known to all template based functions, including QVariant. F. 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. Q_DECLARE_METATYPE, as pointed out by @SingerOfTheFall, would register template based type into QVariant (so it can be retrieved using qvariant_cast<T>()). It manages an insane amount of static variables and sets a static global pointer of. I'm using Qt 5. Call qRegisterMetaType() to make type available to non-template based functions, such as the queued signal and slot connections. Q_DECLARE_METATYPE(Pkg) and this does not give compile errors, but in my main. The object it returns should also be a member of the factory class. Q_DECLARE_METATYPE QMetaType::type. Has anyone else encountered this?See also qRegisterMetaType(). 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. Output:Additionally Q_DECLARE_METATYPE and qRegisterMetaType are not purposed to be used for QObject derived classes. Read and abide by the Qt Code of Conduct. Also, this Q_DECLARE_METATYPE(SharedTestClass) shouldn't be needed. typedef QVector<QSharedPointer<Tester> > TestPointerVector;. 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. See also Thread Support in Qt, QObject::connect(), qRegisterMetaType(), and Q_DECLARE_METATYPE(). Greetings. template <typename T> struct QMetaTypeId<Container<T>>. Reply Quote. If you want both, then register both. 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. 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. Any idea what I'm missing please? BTW, no problem at all using Schedule in QMetaProperty or QVariant. Posted by Unknown at 2:06 AM. The class is used as a helper to marshall types in QVariant and in queued. It associates a type name to a type so that it can be created and destructed dynamically at run-time. Consider the specific case of qRegisterMetaType. QtCore. 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. This function is useful to register typedefs so they can be used by QMetaProperty, or in QueuedConnections. " –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. Q_DECLARE_METATYPE QMetaType::type. 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. I my real world application Context holds a large number of physical quantities (masses, forces, velocities,. QMetaType.