Hi guys, i know that similar topic was here recently, but this one much more simple and precise. 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. But it still absolutely simple. Here how the program works: When program starts - function in worker object called, it runs eternally, if trigger variable is true - signal emits message in mainWindow(it will mean that everything works): void worker::mainFlow() { while(true) { if(trigger) sentInt(75); Sleep(1000); } } Here how connect looks in main constructor: connect(w1, SIGNAL(sentInt(int)), this, SLOT(receiveInt(int))); Such simple app works, but if i change parameters from int to "signed long long" it will give message during runtime and signal won't be emitted: QObject::connect: Cannot queue arguments of type 'signed long long' (Make sure 'signed long long' is registered using qRegisterMetaType().) No matter how much i read stuff from google, nothing helps. Some offer use qRegisterMetaType() - it changes nothing, some - update Qt, but i already have last version 5.12. In my recent 5.10 was no such problems, what should ordinary users do, to resolve such basic stuff?

@ Engelard said in Cannot queue arguments of type... : Why? I really can not understand, it's basic type which is often used by everyone everywhere, it's not some vector or some custom type... Doesn't matter. Qt has to know how to pack it for queued message transmission. And i can't find single simple example for "qt register meta type" in google. I'd understood if i want to pass my custom type like struct or so, but it is essential type. qRegisterMetaType<signed long long>() - do nothing. Usually it goes in a pair: Q_DECLARE_METATYPE(TypeName) goes in the header, and then in the source at runtime registration is done with: qRegisterMetaType<TypeName>();

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Cannot queue arguments of type...

Unsolved General and Desktop

21 Posts 9 Posters 23.1k Views 3 Watching

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Christian Ehrlicher
Lifetime Qt Champion
wrote on last edited by

#21

A slot can not take non-const references. Especially not when it's a queued connection.
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