Is the timer created by create_wall_timer() monotonic? i.e., guaranteed never to jump backwards (or forwards) due to midnight, daylight savings time, user changing the system clock, clock adjustments via NTP, etc?
Originally posted by high12noon on ROS Answers with karma: 3 on 2021-08-10
Post score: 0
According to rclcpp::timer docs, std::chrono::steady_clock is used,
using WallTimer = GenericTimer< CallbackType, std::chrono::steady_clock >
Quoting from std::chrono::steady_clock docs,
Class std::chrono::steady_clock represents a monotonic clock. The time points of this clock cannot decrease as physical time moves forward and the time between ticks of this clock is constant. This clock is not related to wall clock time (for example, it can be time since last reboot), and is most suitable for measuring intervals.
So to answer your question, Yes, it is guaranteed never to jump backwards (or forwards) due to midnight, daylight savings time, user changing the system clock, clock adjustments via NTP, etc
Originally posted by ijnek with karma: 460 on 2021-08-10
This answer was ACCEPTED on the original site
Post score: 2
Comment by shonigmann on 2021-08-10:
And adding a small note for anyone who is curious, from std::chrono::duration docs,
Note: each of the predefined duration types up to hours covers a range of at least ±292 years.
So overflow also won't be an issue, at least in our lifetime
