The Qt Location module provides developer access to geocoding and navigation information. It can also allow the user to do a place search for which the data needs to be retrieved, either from a server or from the user's device.
At the moment, Qt's map view does not support C++, only QML. This means that we can only use QML script to alter anything related to the visual—displaying a map, adding a marker, and so on; on the other hand, we can use the C++ classes provided by the module to obtain information from a database or from a service provider, before displaying it to the user via QML.
Just a quick note, QML (Qt Modeling Language) is a user interface markup language for Qt Quick applications. Since QML is powered by the JavaScript framework, its coding syntax is almost similar to the JavaScript. If you need an in-depth learning on QML and Qt Quick...