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difference between Time.now() and /clock

time

asked 2012-05-15 05:04:28 -0500

max
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Hello!I'm new to ROS and now i have checked that to print time on screen (for example) i can use ros::Time::now() or subscribe to /clock and get time from the message. Anybody can tell me if there are differencies between these two ways? thanks,

max

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answered 2012-05-15 06:55:20 -0500

DimitriProsser

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These two options represent the same time. In code, you should definitely use ros::Time::now(). It will get you the current ROS time that is being published to /clock without most of the overhead involved with subscribing to the topic yourself. Plus, it looks a lot better in your code.

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Isn't /clock only published by simulation and only used by ros::Time when use_sim_time is true? I think on a real system, subscribing to it would just not work.