How do I convert a std::chrono::time_point to long and back?
网页And this next statement becomes essentially a no-op (simply makes a copy and does not make a conversion): auto value = std::chrono::duration_cast<std::chrono::milliseconds>(epoch); Here: long duration = value.count(); In both your and my code, duration holds the number of milliseconds since …
How do you print a C++11 time_point? - Stack Overflow
网页2013年4月3日 · Of course in your case, since you are just looking to print the time point, there is no need for it to be at any specific resolution, so you can just declare time_point to be the same type as what system_clock::now() returns to begin with. A simple way to do that is to use the system_clock::time_point typedef: system_clock::time_point time_point;
How to create a time point from milliseconds since Unix epoch?
网页2021年3月14日 · 1. return std::chrono::system_clock::from_time_t(time_t{0})+std::chrono::milliseconds(m); this returns a system clock time point. Like most things calendar/time related, the odds this covers things like leap seconds properly is low; odds are your ms since unix epoch value might be off …
Difference between two time_point instances is not a duration?
网页2013年4月26日 · The difference between two time points is indeed a duration; but you can't implicitly convert one duration type to another, since that could silently lose precision. If you want to reduce the precision from system_clock::duration to seconds, then you need to make the conversion explicit using a duration_cast: delay = duration_cast<std::chrono ...
Efficiency of using time_t and time_point in C++ - Stack Overflow
网页2015年3月11日 · If size of time_point instance is large, the copying of time_point instances may highly affect the processing time if we use STL data structures which stores the classes containing time_point instances. – ysrhung. Mar 11, 2015 at 9:34. 1. then benchmark it. (if you didn't benchmark it, then chances are it doesn't matter that much.)
c++ - std::chrono::time_point set to now - Stack Overflow
网页2012年12月4日 · To portably deal with this situation, you can query a time_point's clock with: time_point::clock I.e. in your implementation steady_clock::time_point::clock isn't steady_clock but system_clock. If you really want a time_point that is compatible with steady_clock::time_point but with millisecond resolution you could do this:
c++11 - Add time duration to C++ timepoint - Stack Overflow
网页Convert time_point to duration or duration to time_point without intermediate. It is inherently impossible to convert a time_point to duration or back directly. Many examples use time_t as intermediate, which is a fine method. I use the method that uses the …
Convert std::chrono::time_point to unix timestamp
网页When interpreted // as UTC this represents the same calendar date and time as the // original, but if we change the timezone to the system TZ then it // represents a time offset from the original calendar time by as // much as UTC differs from the local timezone. std::tm m = *std::gmtime(&l); // Treat the new calendar time as offset time in the ...
How to convert std::chrono::time_point to std::tm without using …
网页2017年5月27日 · If you don't know what time the computer booted up, there is no way to convert that time_point to any calendar system. That being said, you were probably talking just about std::chrono::system_clock::time_point, as this time_point, and only this time_point, is required to have a deterministic relationship with the civil (gregorian) calendar.
Creating a `std::chrono::time_point` from a calendar date known at ...
网页2018年9月9日 · std::chrono::system_clock::time_point has no way to represent any time point that is during a leap second. My tz.h library has another clock/time_point set: utc_clock , which can represent leap seconds, but one would not be able to form a constexpr utc_clock::time_point because the leap second data is not compile-time information.