Revision history [back]

No, there is no spin_once in rospy. In rospy the subscriber's callbacks are executed in separate threads. Google quickly produces these old questions including answers:

• http://ros-users.122217.n3.nabble.com/rospy-version-of-spinOnce-td180442.html
• http://ros-users.122217.n3.nabble.com/ros-spinOnce-equivalent-for-rospy-td2317347.html
• http://answers.ros.org/question/30490/rospy-suscriber-run-a-callback-once-using-rospyspin/

To translate your loop from C++ you could either check periodically in a loop in the main thread, or check in each of the callbacks. Either way you likely need some thread synchronization.