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int callback

asked 2012-07-26 07:07:57 -0500

Rydel gravatar image

Is it possible to have a callback function other than type void? If yes, how would you handle a situation where you call ros::spinOnce() and say you are subscribing to two different topics each with their own callback function... how would you store the variable that one of the callback functions returned?

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answered 2012-07-26 07:10:21 -0500

dornhege gravatar image

updated 2012-07-27 02:10:39 -0500

I would say: No.

For the reason that you basically explained yourself: What would one do with the return value?, What is the meaning of that?

PS: Maybe, your intended usage of ros::spinOnce is based on a misconception. ros::spinOnce will not call one callback, but all available callbacks at the time. For more information, see: http://www.ros.org/wiki/roscpp/Overview/Callbacks%20and%20Spinning

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Possibly a boolean return? That could be useful in some scenario.

allenh1 gravatar image allenh1  ( 2012-07-26 09:55:04 -0500 )edit
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But who would use that? Callbacks come from spin, so what should happen in spin if a callback returns false? Things like error handling in client code should not go through spin, but be handled directly by the callback (IMO). Figuring out what callback caused a false return would also be messy.

dornhege gravatar image dornhege  ( 2012-07-27 02:02:23 -0500 )edit

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Asked: 2012-07-26 07:07:57 -0500

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Last updated: Jul 27 '12