howto send a reply using QDBusMessage

[HERC]

Hello,

I want to send a reply over DBUs before the end of my slot method. According to the QT document I have to use QDBusMessage QDBusMessage::createReply ( const QVariant & argument ) const.

Suppose I have the follow slot

int getValue(QString key);

int getValue(QString key);

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How can I send a reply over the DBUS? I tried it like this

Int getValue(QString key) {
QDBusMessage msg;
QVariant v(2);
msg.createReply(v)
bus.send(msg);
 
Return 0;
}

Int getValue(QString key) {
QDBusMessage msg;
QVariant v(2);
msg.createReply(v)
bus.send(msg);

Return 0;
}

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Where

bus= QDBusConnection::sessionBus();

bus= QDBusConnection::sessionBus();

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But I get the follow DBUS error
QDBusConnection: error: could not send invalid message to service “”

[HERC]

it seems that I have to implement the follow slot

int getValue(QString key,const QDBusMessage&);

int getValue(QString key,const QDBusMessage&);

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and the slot implemantation is

int getValue(QString key,const QDBusMessage& msg) {
 
QVariant v(2);
QDBusMessage reply= msg.createReply(v)
QDBusConnection::sessionBus().send(reply);
 
Return 0;
}

int getValue(QString key,const QDBusMessage& msg) {

QVariant v(2);
QDBusMessage reply= msg.createReply(v)
QDBusConnection::sessionBus().send(reply);
 
Return 0;
}

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However I recevied 2 replys in that case .
According to the QT document no reply should be send on return.

[HERC]

I have to set

msg.setDelayedReply(true);

msg.setDelayedReply(true);

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