rosmsg show Num error
I'm following the ROS Tutorial ''Creating a ROS msg and srv'' and meet a problem. When I type
$ rosmsg show Num
It shows
Unable to load msg [beginner_tutorials/Num]: /home/xxx/catkin_ws/src/beginner_tutorials/msg/Num.msg: Invalid declaration: int 64 num
can anybody explain this error? thanks in advance