Revision history [back]

I won't work like that.

A callback is called back, i.e. it will be triggered iff there is data available from a publisher. You cannot request data from a callback.

The correct way to solve the problem is to synchronize the callbacks, i.e. collect data from both and only trigger your specific code if data from both is OK. For some common use cases, there already exist ROS methods, e.g. Stamped data from one callback and a transformation from TF.