Call a QML function from C++ Class?

Question

I want to pass variables from my C++ class to a function in my QML class so that the function can use them.

I am trying to use a signal and connection but it's not working.

Here's my relevant code:

main

...
qmlRegisterType<Client>("Client", 1, 0, "Client");
QQmlApplicationEngine engine;
engine.load(QUrl(QStringLiteral("qrc:/map.qml")));
...

cpp header

class Client : public QDialog
{
    Q_OBJECT

public:
    explicit Client(QWidget *parent = nullptr);
...

public slots:
    void callDoAddMarker(float latitude, float longitude);

signals:
    void doAddMarker(float latitude, float longitude);

cpp class

void Client::someFunction(UINT16 array[]) {

    ...

    callDoAddMarker(latit, longit);
}

void Client::callDoAddMarker(float latitude, float longitude) {
    emit doAddMarker(latitude, longitude);
}

and in QML

import Client 1.0

...

function addMarker(latitude, longitude) {
    ...
}

Client {
    id: client
}

Connections {
    target: client
    onDoAddMarker: {addMarker(latitude, longitude)}
}

Can someone tell me what I'm doing wrong? Any help is greatly appreciated!

EDIT: Adding in my main to show how I register the cpp class with QML, not sure if this is correct.