Qt register meta type. There is a name index for fast lookup of the meta type id.

Qt register meta type If you register your types directly from the main program, you're still facing the same problem. Jan 15, 2014 · Type "MyType" has id: 1024 ; register status: true QObject::connect: Cannot queue arguments of type 'MyType' (Make sure 'MyType' is registered using qRegisterMetaType(). id ( [ arg__1=0 ] ) ¶ Parameters Qt's meta-object system provides the signals and slots mechanism for inter-object communication, run-time type information, and the dynamic property system. This is the reason I preach around this forum to Jan 18, 2016 · actually you can register types under QMetaType system so you can work with the classes using QVariant. So my best guess it that something is referred to in Qt before being initialized because you call qRegisterMetaType at the global scope and that is executed before Qt's globals were initialized. Then it's useless since then Qt::AutoConnection evaluates to Qt::DirectConnection. Declaring a template class a metatype in QT. ) Dec 8, 2020 · @JKSH said in Correct syntax to register object reference using qRegisterMetaType?: It is easy to cause crashes this way. [static] bool QMetaType:: hasRegisteredConverterFunction () Returns true, if the meta type system has a registered conversion from type From to type To. I had a problem with a signal and slot which I found was reported as: QObject::connect: Cannot queue arguments of type 'QJsonObject&' (Make sure 'QJsonObject&' is registered using qRegisterMetaType(). 14. After all, why should we require you to call QMetaType::registerEqualsComparator() when we could already know this by simply looking at the type? Jan 29, 2016 · I'm doing some R&D work on properties and ran into some strange behaviour: I've declared two classes derived from QObject: class NestedProperty: public QObject { Q_OBJECT Q_PROPERTY(QString name READ name WRITE setName) Q_PROPERTY(int count READ count WRITE setCount) Registers T with the Qt D-Bus Type System and the Qt meta-type system, if it's not already registered. Since Qt 4. MyClass. ) May 1, 2017 · Note that you are technically lying to the meta type system. The custom Message type can also be used with direct signal-slot connections. Any class or struct that has a public default constructor, a public copy constructor and a public destructor can be registered in QMetaType. 1. ) Dec 7, 2024 · I've got a signal and slot connection with a custom type called MyMediaInfo. ) Dec 8, 2020 · @SPlatten said in Correct syntax to register object reference using qRegisterMetaType?: not for the ones where I've used Qt::DirectConnection. Other types can be registered to qt meta data system. Welcome to Qt Centre. Dec 8, 2020 · @JonB , thank you, I'll take a look. userType(); //< !!! QMetaProperty::userType() !!! fixed the problem. 1 Reply Last reply Apr 29, 2017 · Registered enumerations are automatically registered also to the Qt meta type system, making them known to QMetaType without the need to use Q_DECLARE_METATYPE(). It is also possible to create "classes" from QML files, these classes inherit QObject But these classes are not registerted on QMetaType system, seems Mar 5, 2009 · You may have to register before you can post: click the register link above to proceed. qobject. Call qRegisterMetaType () to make types available to non-template based functions, such as the queued signal and slot connections. Qt Meta object magic. It looks like this is right, because I tested QSignalSpy, QObject::connect() (direct and queued connection) and QVariant - with just using Q_DECLARE_METATYPE(type) and none of them needed a explicit call to Jan 7, 2021 · Hello, Can someone tell me about how to register a metatype in pyqt5. Feb 24, 2022 · Qt源码解析 索引 目录 Qt源码解析 索引 类QMetaType 辅助类QtMetaTypePrivate 成员函数qMetaTypeId 成员函数type 成员函数create 成员函数destroy 相关宏Q_DECLARE_METATYPE 相关非成员函数qRegisterMetaType 类QMetaType 该类用作在 QVariant 以及排队的信号和槽连接中编组类型的帮助程序。 Dec 4, 2020 · Can Qt types can be register in meta object system? I tried to register enum QtMsgType in class inherited from QObject with qobject macro and qenum macro and in class with qgadget. Mar 16, 2017 · From Qt documentation: Ideally, this macro should be placed below the declaration of the class or struct. So thank you again You're welcome. See full list on doc. 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: Feb 19, 2013 · Hello! I want to do some non-basic signal-slot connections between a QThread and the MainWindow class and reading Qt's Assistant documentation I found that I need to use qRegisterMetaType() to register the data-container types in case I'm using non-standart types, and this is what I did: struct analysis_results { POSITION share_id; TYPE analysis_type; @SPlatten said in Correct syntax to register object reference using qRegisterMetaType?: @kshegunov , I am using const QJsonObject& for my signal arguments, these are working, the only thing that is displayed in the Application Output is the message I've Jan 29, 2016 · I'm doing some R&D work on properties and ran into some strange behaviour: I've declared two classes derived from QObject: class NestedProperty: public QObject { Q_OBJECT Q_PROPERTY(QString name READ name WRITE setName) Q_PROPERTY(int count RE QObject::connect: Cannot queue arguments of type 'QMap<QString,long long unsigned int>' (Make sure 'QMap<QString,long long unsigned int>' is registered using qRegisterMetaType(). QMetaObject::indexOfEnumerator returns -1 but i Returns true, if the meta type system has a registered mutable view on meta type id fromType of meta type id toType. io Type names can be registered with QMetaType by using either qRegisterMetaType () or registerType (). Using const MyClass & argument type is compatible with MyClass in Qt meta-object system. As said in int qRegisterMetaType() documentation: To use the type T in QVariant, using Q_DECLARE_METATYPE() is sufficient. ) Mar 24, 2016 · This is a very extensive topic and is mostly an implementation detail, but Qt has statics of it's own. I'm not experience any other problems, crashes or bugs. Jun 30, 2023 · You can simply remove it. For pointer types, it also requires that the pointed to type is fully defined. *QMetaEnum::enumName() returns nullptr in both cases but compiler doesnt say something about what i do wrong. Compares the objects at lhs and rhs. Oct 16, 2013 · Register a Meta Type in Qt. Jan 14, 2013 · You may have to register before you can post: click the register link above to proceed. Asking for help, clarification, or responding to other answers. Dec 19, 2013 · You would need to use the following method for register your custom type though. when using QVariant::fromValue () it will take care of that. Aug 14, 2017 · uint8_t is the typedef for unsigned char. Jan 7, 2021 · QObject::connect: Cannot queue arguments of type 'QVector<int>' (Make sure 'QVector<int>' is registered using qRegisterMetaType(). Then you need to register and declare your new metatype. Both objects need to be of type typeId. Usually it goes in a pair: Q_DECLARE_METATYPE(TypeName) @SPlatten said in Correct syntax to register object reference using qRegisterMetaType?: Only removing the & gets rid of this but then I'm back to the original problem, so how do I get over this? You don't. Declare the type as a Qt meta type by adding a Returns true, if the meta type system has a registered conversion from meta type id fromType to toType This function was introduced in Qt 5. 2] template <typename From, typename To> bool QMetaType:: hasRegisteredConverterFunction () Dec 10, 2018 · And i can't find single simple example for "qt register meta type" in google. There is a name index for fast lookup of the meta type id. The latter still requires qRegisterMetaType. And because the pair type is registered already, you don't have to worry when using it as QList type Dec 10, 2018 · And i can't find single simple example for "qt register meta type" in google. May 6, 2013 · template <typename Type> class MetaTypeRegistration {public: inline MetaTypeRegistration() {qRegisterMetaType<Type>(); qRegisterMetaTypeStreamOperators<Type>(); Jul 23, 2014 · Thanks for contributing an answer to Stack Overflow! Please be sure to answer the question. As far as my superficial understanding of QML goes, you define objects (and their hierarchies) in your qml file, so what would you want to register with the meta-type system exactly? Kin May 5, 2014 · Solution: Registration of mata-type was not an issue. This is an Feb 26, 2014 · Qt considers MyClass and MyClass* two different unrelated types. QtCore. Jul 25, 2018 · QObject::connect: Cannot queue arguments of type 'QMap<QString,long long unsigned int>' (Make sure 'QMap<QString,long long unsigned int>' is registered using qRegisterMetaType(). Over 90 percent of questions asked here gets answered. May 4, 2012 · If you just want to store a custom type within a container (<code>lst</code>) there is no need to declare or register the custom type. But this is nasty and it is hard to believe there is no solution in Qt. The slot is called in a different thread. It enables things such as QVariant wrapping of custom types, copy of queued connection arguments, and more. Returns true, if the meta type system has a registered conversion from meta type id fromType to toType This function was introduced in Qt 5. [static] template <typename From, typename To> bool QMetaType:: hasRegisteredConverterFunction Returns true, if the meta type system has a registered conversion from type From to type To. Use the non-static compare method instead. [static, since 5. 2. I created new project with name "tests", the only significant thing i did - added new class of worker so i'd be able use QThreads. QVariant does not have constructor taking a template value. Qt::DirectConnection. QMetaObject::indexOfEnumerator returns -1 but i Dec 10, 2018 · And i can't find single simple example for "qt register meta type" in google. Dec 8, 2020 · I had a problem with a signal and slot which I found was reported as: QObject::connect: Cannot queue arguments of type 'QJsonObject&' (Make sure 'QJsonObject&' is registered using qRegisterMetaType(). PLS give me an example of code for registering a new meta type. You shall not register references as meta-types. ) I googled this and found some related topics but can't really understand when/where/how to register my QMap, can someone put me on the right track please ? Jul 27, 2011 · [quote author="genC" date="1311851619"]Oh, one last thing: why can't the QVariant of type QObject* be converted to a Class1* (using QVariant::convert(Type t))?[/quote]Because QVariant::type() returns 2 different type ids for Class1* and QObject*, and you can see in the source code of QVariant::canConvert(Type) that if the two type ids are different the functions returns false except for a few Dec 8, 2020 · I had a problem with a signal and slot which I found was reported as: QObject::connect: Cannot queue arguments of type 'QJsonObject&' (Make sure 'QJsonObject&' is registered using qRegisterMetaType(). result is set to less than, equal to or greater than zero, if lhs is less than, equal to or greater than rhs. Kind Regards, Sy. This is an overloaded function. ) Nov 22, 2012 · You may have to register before you can post: click the register link above to proceed. ) Nov 30, 2012 · In C++ if you wan't to use some type in queued connection type you should call qRegisterMetaType<MyType>("MyType"). To register a custom type for use with queued signals and slots, such as those used in cross-thread communication, see the Queued Custom Type Example. ) May 30, 2020 · Thanks for contributing an answer to Stack Overflow! Please be sure to answer the question. ) Jun 9, 2017 · What is even more frustrating is that, although Qt supports QMetaType::registerConverter(MemberFunction function) to register converter function, you can't register the converter of two basic meta types. . Oct 21, 2020 · In 5. PySide6. Different story when using your own custom type. ) QObject::connect: Cannot queue arguments of type 'QV Jan 28, 2016 · Is it allowed to register in the meta-object system multiple times the same data type? Are there any side effects for that? I need to register QPointer<QObject> for a widget I'm developing, and I was wondering if I could call the qRegisterMetaType<QPointer<QObjecT>>() in the constructor safely. This trick uses static initialization. (Copy) Constructor and Destructor (in-place or not). @SPlatten said in Correct syntax to register object reference using qRegisterMetaType?: Only removing the & gets rid of this but then I'm back to the original problem, so how do I get over this? You don't. Quoting from What's New in QMetaType + QVariant. This is what I've done: class blabla: public QThread { Q_OBJECT . If that is not possible, it can be put in a private header file which has to be included every time that type is used in a QVariant. Apr 29, 2013 · I have a class and I want to use it in a Qvariant, therefore I need to Declare and Register the Meta type. This function requires that T is a fully defined type at the point where the function is called. Type is not registered, please use the Q_DECLARE_METATYPE macro to make it known to Qt's meta-object system. QVariant. Class name from QMetaProperty. Yeah, what the other guy said Hi guys, i know that similar topic was here recently, but this one much more simple and precise. Note that for enum types, you no not even need to call qRegisterMetaType() in these cases. Oct 12, 2018 · I have a C++ class called MyClass. QMetaType. The reason is: In qobject. ) QObject::connect: Cannot queue arguments of type 'QVector<int>' then my software crashes suddenly. [static] bool QMetaType:: hasRegisteredConverterFunction Returns true, if the meta type system has a registered conversion from type From to type To. How to use a custom Qt type with a QML signal? 1. One of them is the StreamOperator. – jack fu Commented Apr 29, 2017 at 12:27 Registers the meta type meta and returns its type Id. This tells you that the metatype system doesn't know the stream operators of your class/structure. Usually it goes in a pair: Q_DECLARE_METATYPE(TypeName) May 3, 2017 · 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. ) @SPlatten said in Correct syntax to register object reference using qRegisterMetaType?: not for the ones where I've used Qt::DirectConnection. It says: qt. Moreover, we considered the registries to be a bit clunky. using fix IDs or using type name). ) I googled this and found some related topics but can't really understand when/where/how to register my QMap, can someone put me on the right track please ? Jul 1, 2019 · You do not need to call qRegisterMetaType() to use a type with QVariant. h line 261 in connect(): Dec 8, 2020 · I had a problem with a signal and slot which I found was reported as: QObject::connect: Cannot queue arguments of type 'QJsonObject&' (Make sure 'QJsonObject&' is registered using qRegisterMetaType(). Note that using MyClass and MyClass* meta types simultaneously in one program is unusual and can cause mistakes and confusion. Dec 29, 2015 · You may have to register before you can post: click the register link above to proceed. Share. They can't ever be such, because they can't be copied. In any case you don't need to delay that to the execution of the main event loop, Qt's meta type system can be used without any application object. You can use Qt's typedef for unsigned char: quint8 and you don't need to register it. qRegisterMetaType<signed long long>() - do nothing. Avoid having to qRegisterMetaType (pointer vs reference When building user interfaces with the Qt Quick module, all QML objects that are to be visually rendered must derive from the Item type, as it is the base type for all visual objects in Qt Quick. ) Dec 8, 2020 · @kshegunov , I am using const QJsonObject& for my signal arguments, these are working, the only thing that is displayed in the Application Output is the message I've raised. Dec 10, 2018 · And i can't find single simple example for "qt register meta type" in google. This works, but only for plugins. Sep 17, 2017 · Intrestingly: What fails is Qt::MouseButton and Qt::MouseEventFlags but not so Qt:MouseButtons (which is only an alias to Qt::MouseButton). Oct 4, 2024 · So you don't have to declare or register the type when using simple QString data as template type. Mar 17, 2022 · Debugging problems caused by these kinds of ambiguity (especially on VS) is difficult and I do not want to make mistakes now which might give me errors later and would consume a lot of my time in figuring out that I registered the type or stream operators incorrectly. Did you also check the Q_DECLARE_METATYPE macro ? You should declare and register the types properly, lying to qRegisterMetaType will get you in trouble in the long run. This article will describe what you Dec 4, 2020 · Can Qt types can be register in meta object system? I tried to register enum QtMsgType in class inherited from QObject with qobject macro and qenum macro and in class with qgadget. You should declare, register and use them separately. I created a multithreaded software and I am getting the warning says: (Make sure 'QVector' is registered using qRegisterMetaType(). Avoid having to qRegisterMetaType (pointer vs reference), concern about const. Jun 13, 2018 · Using Q_ENUM automatically registers enum with meta-object system so you don't need to add Q_DECLARE_METATYPE(MyEnum) But to use enum in queued signal slot connections, properties you need to register meta type. Read and abide by the Qt Code of Conduct 1 Reply Last reply Jan 7, 2021 · QObject::connect: Cannot queue arguments of type 'QVector<int>' (Make sure 'QVector<int>' is registered using qRegisterMetaType(). 2] template <typename From, typename To> bool QMetaType:: hasRegisteredConverterFunction () @SPlatten, Removing the & so the signal and slot parameters are simply QJsonObject compiles and works, but I'm concerned that the could use more stack and a reference. 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. This operator is used by QSettings to write and read QVariant in a configuration file. With asynchronous method invocations, the parameters must be of types that are known to Qt’s meta-object system, because Qt needs to copy the arguments to store them in an event behind the scenes. Improve this answer. In order to use it with custom types from Qt Meta System QVariant::seValue must be used. Provide details and share your research! But avoid …. 2. So why I need to call qRegisterMetaType() in order to let type in SomethingElse function of Class C get correct type value?. This function was introduced in Qt 5. This means I could circumvent the problem with Qt::MouseButton by just changing the type to the plural, and the Qt::MouseEventFlags could be passed as int as it is indeed not available in QML (should be Qt. This function Dec 10, 2018 · And i can't find single simple example for "qt register meta type" in google. @SPlatten The signal argument type is "OK", insofar as it would work OK with non-cross-thread direct connection connect()s. Dec 16, 2014 · I have a class that is a subclass of QObject that I would like to register as a meta-type. Specifying a connection type is not needed in most of the cases. If you ever wondered what does Q_DECLARE_META_TYPE or qRegisterMetaType do and when to use (or not to use) them, read on. core. More information on using custom types with Qt can be found in the Creating Custom Qt Types document. . 12） 元类型之Q_DECLARE_METATYPE; QT的QVaiant结合自定义的结构体 使用非QMetaType类型缺少Q_DECLARE_METATYPE宏定义错误; QT的qRegisterMetaType和qRegisterMetaType; Qt元类型（MetaType） Qt中注册QML类型 If you want to create instances of QObject classes by name, you can use QMetaObject instead of QMetaType. Register the type. Thanks. Usually it goes in a pair: Q_DECLARE_METATYPE(TypeName) May 16, 2016 · When a queued signal is actually needed, Q_ENUM with Qt::QueuedConnection (or Qt::BlockingQueuedConnection) connection works, but Qt::AutoConnection (the default parameter) does not. int main(int argc, char *argv[]) { // Register types on startup qRegisterMetaType<StandardData>(); // Continue with the program // } Trick with Static Initialization. Oct 10, 2016 · It is. Q_DECLARE_METATYPE doesn't work at all. Apr 22, 2015 · QMetaType is Qt's way to have run-time dynamic information about your types. ) And i can't find single simple example for "qt register meta type" in google. Apr 22, 2015 · Here is the list of information kept for each type in the meta-type system: The Type Name as registered. The QObject documentation states that the copy-constructor should be private, but the QMetaType documentation states that a type should have a public default constructor, a public copy constructor, and a public destructor. ) Jan 7, 2021 · QObject::connect: Cannot queue arguments of type 'QVector<int>' (Make sure 'QVector<int>' is registered using qRegisterMetaType(). Dec 4, 2020 · Can Qt types can be register in meta object system? I tried to register enum QtMsgType in class inherited from QObject with qobject macro and qenum macro and in class with qgadget. In general, you only need Q_DECLARE_METATYPE(). QMetaObject::indexOfEnumerator returns -1 but i @SPlatten , Removing the & so the signal and slot parameters are simply QJsonObject compiles and works, but I'm concerned that the could use more stack and a Mar 28, 2013 · Also check for a message in the console that says something like unable to save/load type XXX (I can't remember exactly the text of the error). h: #pragma once #include &lt;QObject&gt; class MyClass : public Mar 2, 2020 · The qmltypes file contains meta-information about the types registered by the plugin. You'll need Q_DECLARE_METATYPE() if you want to store your type within a QVariant and you will additionally need qRegisterMetaType<>() if you want to dynamically create and destroy objects of that type at runtime, mostly for queued signal and slots connections @kshegunov , I am using const QJsonObject& for my signal arguments, these are working, the only thing that is displayed in the Application Output is the message I've raised. To start viewing messages, select the forum that you want to visit from the selection below. Usually it goes in a pair: Q_DECLARE_METATYPE(TypeName) May 25, 2019 · Register a Meta Type in Qt. 3beta) so I figured to ask a new question. 8. Is there any way to reserve type IDs or to register types with predefined IDs? Dec 8, 2020 · You shall not register references as meta-types. ) Jan 29, 2016 · Nevertheless, your hint int meta_prop_type = meta_prop. ) Bug is reproducable only if a queued connection is used (when objects are in different threads or explicit Qt::QueuedConnection is used) and MyType is declared inside a namespace. Jan 14, 2013 · Depending on what you do you might not need explicit qRegisterMetaType () calls at all, e. First, you have to declare your constructor as invokable: class ClassA : public QObject { Q_OBJECT public: Q_INVOKABLE ClassA() { mName = "lol"; } ~ClassA(); void showName() { std::cout << mName << std::endl; } std::string mName; }; Dec 7, 2024 · I've got a signal and slot connection with a custom type called MyMediaInfo. ) Dec 8, 2020 · I had a problem with a signal and slot which I found was reported as: QObject::connect: Cannot queue arguments of type 'QJsonObject&' (Make sure 'QJsonObject&' is registered using qRegisterMetaType(). Usually it goes in a pair: Q_DECLARE_METATYPE(TypeName) I had a problem with a signal and slot which I found was reported as: QObject::connect: Cannot queue arguments of type 'QJsonObject&' (Make sure 'QJsonObject&' is registered using qRegisterMetaType(). Qt Centre is a community site devoted to programming in C++ using the Qt framework. Usually it goes in a pair: Q_DECLARE_METATYPE(TypeName) Dec 8, 2020 · @SPlatten said in Correct syntax to register object reference using qRegisterMetaType?: not for the ones where I've used Qt::DirectConnection. This Item type is implemented by the QQuickItem C++ class, which is provided by the Qt Quick module. From what I could discern QMetaProperty::type returns QVariant::UserType for all user types, and that's why you need to call int QMetaProperty::userType() to get the correct type Dec 8, 2020 · I had a problem with a signal and slot which I found was reported as: QObject::connect: Cannot queue arguments of type 'QJsonObject&' (Make sure 'QJsonObject&' is registered using qRegisterMetaType(). connect: QObject::connect: Cannot queue arguments of type 'MyMediaInfo*' (Make sure 'MyMediaInfo*' is registered using qRegisterMetaType(). I replaced the parameter again with a pointer and this works fine to. 3. 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. You only need to call qRegisterMetaType() if the type will be used in queued signal/slots connections, or with the QObject::property API. Qt Creator and other tools can then refer to this information in order to provide you with better analysis of your code. Declare new types with Q_DECLARE_METATYPE () to make them available to QVariant and other template-based functions. Jan 18, 2016 · Hello, Correct me if I'm wrong, but you don't define classes in QML. I'm not sure how to do this in python but probably you should add similar call with QTextCursor – Dec 4, 2020 · Can Qt types can be register in meta object system? I tried to register enum QtMsgType in class inherited from QObject with qobject macro and qenum macro and in class with qgadget. Apr 29, 2017 · So we have to use qRegisterMetaType to register a custom type first then the QMetaType::type(const char *typeName) will be able to find correct type from meta data. I'd understood if i want to pass my custom type like struct or so, but it is essential type. You should Qt自定义类型注册以及Q_DECLARE_METATYPE; Q_DECLARE_METATYPE()和qRegisterMetaType基本使用方法（5. But the problem is that you are Sep 14, 2012 · With some effort maybe I could write special work-around routines that detect the type of the QVariant and use special handling for user types (e. g. The meta-object system is based on three things: The QObject class provides a base class for objects that can take advantage of the meta-object system. cpp). Kind regards. Pattern to register metatypes in Qt. Even though we now have an Adaptor to wrap an object and an Interface to talk to it, you will not be able to compile them as some extra things are necessary for the Qt Meta object system to be able to process the custom type. qt. ) Jun 30, 2019 · This page states, that the registration is done automatically by the moc if it can determine that the type may be registered as meta-type. Meta types are not automatically registered. My code works with Qt5, but not with Qt6. QMetaObject::indexOfEnumerator returns -1 but i Jan 17, 2020 · Register a Meta Type in Qt. This class is registered as an uncreatable type so it can be referred by name in QML. Registration is not required for most operations; it's only required for operations that attempt to resolve a type name in string form back to a QMetaType object or the type's ID. 0, the QML engine copies the information from the property metatypes into a custom datastructure, called PropertyCache. Usually it goes in a pair: Q_DECLARE_METATYPE(TypeName) Dec 8, 2020 · @SPlatten said in Correct syntax to register object reference using qRegisterMetaType?: Only removing the & gets rid of this but then I'm back to the original problem, so how do I get over this? You don't. MouseEventCreatedDoubleClick) Can Qt types can be register in meta object system? I tried to register enum QtMsgType in class inherited from QObject with qobject macro and qenum macro and in class with qgadget. There is a trick that can be used to call qRegisterMetaType without modifying any non-related file (like main. 15 and 6. Hi, I have been searching but nothing I found worked for me (using Qt 5. Usually it goes in a pair: Q_DECLARE_METATYPE(TypeName) Apr 20, 2011 · Qt meta-object system is able to register a large number of operators for custom types. Returns true, if the meta type system has a registered conversion from meta type id fromTypeId to toTypeId. Usually it goes in a pair: Q_DECLARE_METATYPE(TypeName) Dec 10, 2018 · And i can't find single simple example for "qt register meta type" in google. The Qt doc on qRegisterMetaType explicitly says : T must be declared with Q_DECLARE_METATYPE(). You have to register your custom type for queued signals because by registering it, Qt can make a copy of it in its event loop (which certainly uses QVariant) and pass it as argument later (when the original passed value is long since out of What is a meta types used for, and how to I register my type as one? From my understanding, you can register your class to be a meta type, which means some extra code is generated for it, which is used by e. By having the property metatype available, we can already speed this up a bit, as we do not have to lookup the metatypes by name. 7, it is even possible to register the same type with different names (useful for typedefs). muuswe hrroeu oew mijl pymb slbv fro uxowpu kou tpw