error expected constructor, destructor, or type conversion before ‘ when trying to register a structure from my C library

Babs

Hello, i'm trying to register a structure in my C library, in order to use it with signals and slots.

#ifndef MQTTMANAGER_H
#define MQTTMANAGER_H

#include <QObject>
#include <QMetaType>

#include "core/interface/MQTTClient.h"



class MqttManager: public QObject
{
    Q_OBJECT

public:
    MqttManager(QObject *parent = 0);
    void setupParameters();
    titanium_DbErrorCode doMqttClientCreate();
    titanium_DbErrorCode doConnect();
    titanium_DbErrorCode doPublish(QString& p_topic,const QString& p_payload, int p_qos=0,int p_retain=false);
    titanium_DbErrorCode doSubscribe(QString p_topic,int p_qos=0);
    void doUnsubscribe(QString& p_topic);
    void doDisconnect();
    void doMqttClientDestroy();
    static void message_Cb(void* p_ReceiverStruct, void* p_Data);
    void signalEmit(QString);
    static  MqttManager* m_manager;



public slots:


signals:
    void messageReceived(QString);

private:

    QString m_hostname;
    int m_port;
    titanium_MQTTClient *m_client;
    titanium_MQTTConnectionSettings m_connectionSettingsMQTT;
    titanium_MQTTOnMessageCallback m_messageCallBack;
    bool m_autoReconnect;


};


Q_DECALARE_METATYPE(titanium_MQTTMessage);

In my main function i use QRegisterMetatype because i have communication between threads:
```

qRegisterMetaType<titanium_MQTTMessage>();

I get the error:
 expected constructor, destructor, or type conversion before ‘;’ token
 Q_DECALARE_METATYPE(titanium_MQTTMessage);
                                          ^

nagesh

@Babs what is this titanium_MQTTMessage?
Is it structure type or instance of structure?

https://doc.qt.io/qt-5/qmetatype.html#qRegisterMetaType-1

It must be declared with Q_DECLARE_METATYPE()

Babs

@nagesh it is a struct type

Babs

@nagesh i did the declaration with Q_DECLARE_METATYPE

Babs

@nagesh thank you it solved i did the QRegisterMetaType just before connecting the signal to slot