* Returns \c true if the \c Updater instance registered with the given \a url * has an update available. * * \warning You should call \c checkForUp

* Returns the \c Updater instance registered with the given \a url. * * If an \c Updater instance registered with teh given \a url does not exist,

* Returns the user-agent string used by the updater to communicate with * the remote HTTP(S) server. * * \note If an \c Updater instance registered

* Returns the index of the joystick with the given \a instance_id if it exists, * otherwise returns -1. * * \param instance_id The SDL instance ID

* Returns a list with all the registered joystick devices */