how to use the sensor_msgs/NavSatStatus ?

edit

First of all, you have to create a subscriber for the sensor_msgs/NavSatFix message. Take a look here on how to create a subscriber http://wiki.ros.org/roscpp/Overview/P... Your callback function should have this signature:

void callback(const sensor_msgs::NavSatFixConstPtr& satfix)

Looking at the link you have provided (http://docs.ros.org/api/sensor_msgs/h...), we can see that the NavSatStatus is provided on an attribute called status. And this attribute stores the actual status in another variable called status (see here http://docs.ros.org/api/sensor_msgs/h...)

Then, in order to print the status, I think your callback function would be something like this:

void callback(const sensor_msgs::NavSatFixConstPtr& satfix)
{
    ROS_INFO("status = %d", satfix.status.status);
}

Let me know if that works.