chrono

std::chrono offer several clocks to measure times. At the same time, I guess the only way a cpu can evaluate time, is by counting cycles. Question 1: Does a cpu or a gpu has any other way to evaluate time than by counting cycles? If that is the case, because the way a computer count cycles will never be as precise as an atomic clock, it means that a "second" ( period = std::ratio<1> ) for a computer can be actually shorter or bigger than an actual second, causing differences in the long run for time measurements between the computer clock and let's say GPS. Question 2: Is that correct? Some

Why did the committee rename monotonic_clock to steady_clock? Vendors are providing monotonic_clock for backwards compatibility so I expect monotonic_clock will linger for a while. It just seems a bit early to deprecate something in C++0x. ;) Edit: The committe has the right and responsibility to rename components the best they can before release as was done in this case. I don't see the big benefit of the rename. N3128 is the proposal that did so and includes the rationale: The implementation of the timeout definition necessarily depends on a steady clock, one that cannot be adjusted. A

C++11 defines high_resolution_clock and it has the member types period and rep . But I can not figure out how I can get the precision of that clock. Or, if I may not get to the precision, can I somehow at least get a count in nanoseconds of the minimum representable time duration between ticks? probably using period ? #include <iostream> #include <chrono> void printPrec() { std::chrono::high_resolution_clock::rep x = 1; // this is not the correct way to initialize 'period': //high_resolution_clock::period y = 1; std::cout << "The smallest period is " << /* what to do with 'x' or 'y' here? */ <

I've got a small problem caused by insufficient documentation of C++11. I'd like to obtain a time since epoch in milliseconds, or nanoseconds or seconds and then I will have to "cast" this value to another resolution. I can do it using gettimeofday() but it will be to easy, so I tried to achieve it using std::chrono. I tried: std::chrono::time_point<std::chrono::system_clock> now = std::chrono::system_clock::now(); But I have no idea what is a resolution of obtained in this way time_point, and I don't know how to get this time as a simple unsigned long long, and I haven't any conception how to

I have been upgrading some old code and have been trying to update to c++11 where possible. The following code is how I used to display the time and date in my program #include <iostream> #include <string> #include <stdio.h> #include <time.h> const std::string return_current_time_and_date() const { time_t now = time(0); struct tm tstruct; char buf[80]; tstruct = *localtime(&now); strftime(buf, sizeof(buf), "%Y-%m-%d %X", &tstruct); return buf; } I would like to output the current time and date in a similar format using std::chrono(or similar) but am unsure how to go about doing so. Any help

I'm trying to use chrono library for timers and durations. I want to be able to have a Duration frameStart; ( from app start ) and a Duration frameDelta; ( time between frames ) I need to be able to get the frameDelta duration as milliseconds and float seconds. How do you do this with the new c++11 <chrono> libraries? I've been working on it and googling ( information is sparse ). The code is heavily templated and requires special casts and things, I can't figure out how to use this library correctly. Is this what you're looking for? #include <chrono> #include <iostream> int main() { typedef