As a matter of fact, you can only use
QNetworkAccessManager if you have an active connection to the Internet. Since you cannot theoretically know the connectivity state, you have to check this at the runtime of the application. With the help of the Bearer API, you can check whether the computer, mobile device, or tablet is online and you can even start a new connection—if the operating system supports it.
The Bearer API mainly consists of four classes.
QNetworkConfigurationManager is the base and starting point. It holds all network configurations available on the system. Furthermore, it provides information about the network capabilities, for example, whether you can start and stop interfaces. The network configurations found by it are stored as
QNetworkConfiguration holds all information about an access point but not about a network interface, as an interface can provide multiple access points. This class also provides only...