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subscribing to 2 topics

asked 2015-03-23 06:50:13 -0500

End-Effector
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Hello,

I want to subscribe to 2 topics in one node and then do some kind of calculations and them publish a TF.

The subscribers that I saw in the tutorials only subscribe to a single topic, do calculations and them publish. How can I make them subscribe to more then one?

For example I need to subscribe to the /odom position of my robot and to the /camera. Different topics, them I want to compute the trajectories but for that I need info from odom and camera.

I also don't understand how I store the information that I get from the callback function, can I use some global variable to store some info and them use that in the other callback function? How do you return info from a callback function?

thx so much.

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answered 2015-03-23 06:55:19 -0500

BennyRe
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You have to create two Subscriber objects, one for '/camera' and one for '/odom'. For both you write an own callback function.

You can't return data from a callback function. In your callback function you can store data to a global variable or to a member variable, which is the preferred way. Then in your main loop process this data.