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Is the 'x' in ConstPtr& x in callback functions specific to message types?

asked 2018-08-31 01:02:04 -0600

J. J. gravatar image

Hi I'm new to ROS and I'm an amateur when it comes to pointers. I just did the subscriber and publisher tutorials and I am currently experimenting and converting them into classes for future use. I noticed that in the callback function it has the following parameters:

 void chatterCallback(const std_msgs::String::ConstPtr& msg)

then I opened another cpp code with a subscriber and found:

  void joyCallback(const sensor_msgs::Joy::ConstPtr& joy);

My question, is 'joy' and 'msg' specifc to use for their message::message type? How can I know what to put after the ConstPtr& say for sensor_msgs::Range? Thank you.

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answered 2018-08-31 02:01:08 -0600

ahendrix gravatar image

No; the variable name is not specific to the message type or the callback. You can name the argument joy or msg or gerorge or whatever you want.

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Thank you. That cleared up my mind.

J. J. gravatar image J. J.  ( 2018-08-31 02:16:42 -0600 )edit

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Asked: 2018-08-31 01:02:04 -0600

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Last updated: Aug 31 '18