pointer for sensor_msgs::LaserScan

edit

So,

I have sensor_msgs::LaserScanPtr& scan_msg being passed in a function. the first line is BOOST::ASSERT(!scan_msg); the second line is BOOST::ASSERT(!scan_msg->ranges);

Problem: it has a compilation error : ! not defined for shared pointer so, I make a change BOOST::ASSERT(!scan_msg->ranges.get()) Now it has compilation error : get not defined for ranges .

What am I supposed to do to see if ranges is not empty ??? (I have considered operator precendence and applied all the parenthesis I could, to no avail).

~Cheers! navderm