Details
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Bug
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Resolution: Invalid
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Not Evaluated
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None
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5.2.0
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None
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Visual studio 2012, Qt 5.2
Description
I'm trying to emit signal with custom type. Type is declared with *Q_DECLARE_METATYPE* and registered with *qRegisterMetaType*.
When I emit a signal, then I get next error to the output stream:
Type "MyType" has id: 1024 ; register status: true
QObject::connect: Cannot queue arguments of type 'MyType' (Make sure 'MyType' is registered using qRegisterMetaType().)
Bug is reproducable only if objects are in different threads and MyType declared inside a namespace.
Sample code:
MyType.h
#define SHOW_BUG
#ifdef SHOW_BUG
namespace NS
{
struct MyType
{
int val;
};
}
Q_DECLARE_METATYPE( NS::MyType );
#else
struct MyType
{
int val;
};
Q_DECLARE_METATYPE( MyType );
#endif
MyClass.h:
#include "MyType.h" namespace NS { class MyClass : public QObject { Q_OBJECT public: MyClass( QObject *parent = NULL ); ~MyClass(); signals: void sendMyType( const MyType& tt ); public slots: void invokeBug(); void getMyType( const MyType& tt ); }; }
MyClass.cpp
#include <QDebug>
namespace NS
{
MyClass::MyClass(QObject *parent)
: QObject(parent)
{
qRegisterMetaType< MyType >();
}
MyClass::~MyClass()
{
}
void MyClass::invokeBug()
{
const int id = qMetaTypeId< MyType >();
const bool test = QMetaType::isRegistered( id );
qDebug() << "Type \"MyType\" has id: " << id << "; register status: " << test;
MyType tt;
tt.val = 42;
emit sendMyType( tt );
}
void MyClass::getMyType( MyType const& tt )
{
qDebug() << "Slot fired: " << tt.val;
}
}
Main.cpp
#include "MyClass.h" int main(int argc, char *argv[]) { QCoreApplication a( argc, argv ); NS::MyClass c1; NS::MyClass c2; QThread thread; thread.start(); c2.moveToThread( &thread ); // Comment this to fix QObject::connect( &c1, &NS::MyClass::sendMyType, &c2, &NS::MyClass::getMyType ); QTimer::singleShot( 0, &c1, SLOT( invokeBug() ) ); return a.exec(); }
If namespace in 'MyType' declaration is removed OR objects are in same thread - then everything is OK.