chrono

Running on Linux (uname says:) Linux 2.6.32-431.29.2.el6.x86_64 #1 SMP Sun Jul 27 15:55:46 EDT 2014 x86_64 x86_64 x86_64 GNU/Linux My tests show that clock_gettime calls with a clock id of CLOCK_MONOTONIC_COARSE are an order of magnitude faster than calls that use a clock id CLOCK_MONOTONIC. Here's a sample output from a test run which called clock_gettime one million times in a tight loop and measured the lapsed time in milliseconds: CLOCK_MONOTONIC lapse 795 CLOCK_MONOTONIC_COARSE lapse 27 This pleases me and makes the profiler results look better, however I was hoping that I could use std:

std::chrono::system_clock::time_point m_BeginFrame = std::chrono::system_clock::now(); std::chrono::system_clock::time_point m_EndFrame = std::chrono::system_clock::now(); std::chrono::nanoseconds m_WorkTime = std::chrono::nanoseconds::zero(); std::chrono::nanoseconds m_WaitTime = std::chrono::nanoseconds::zero(); auto invFpsLimit = std::chrono::nanoseconds(1e9 / fpsLimit()); // main loop while (!glfwWindowShouldClose(m_pScreen->glfwWindow())) { m_WaitTime = m_BeginFrame - m_EndFrame; m_EndFrame = std::chrono::system_clock::now(); m_WorkTime = m_EndFrame - m_BeginFrame; // if need sleep if (m

Is it possible to get the actual millis since I-don't-know in a C++-programm like System.currentTimeMillis() in Java? I know time() , but I think it's not exactly enough to measure short times, is it? It's part of the language standard these days (some years now): See it Live On Coliru #include <chrono> #include <iostream> int main() { using namespace std::chrono; auto epoch = high_resolution_clock::from_time_t(0); // ... auto now = high_resolution_clock::now(); auto mseconds = duration_cast<milliseconds>(now - epoch).count(); std::cout << "millis: " << mseconds; } In C++ you also have clock()

I'm learning <chrono> library, and considering the std::chrono::duration class, is there any specific reason to base it on seconds? For example a variable to store seconds would be chrono::duration<int> two_seconds(2); and all other time spans require relating them to seconds, like chrono::duration<int, ratio<60>> two_minutes(2); chrono::duration<int, ratio<1, 1000>> two_milliseconds(2); chrono::duration<int, ratio<60 * 60 * 24>> two_days(2); Are there any reasons to base duration on seconds and not on minutes, hours, etc.? Seconds are chosen because it's the basic time unit in both the SI

Is there a convenient way to format std::chrono::duration to a specified format? std::chrono::high_resolution_clock::time_point now, then; then = std::chrono::high_resolution_clock::now(); // ... now = std::chrono::high_resolution_clock::now(); auto duration = now - then; // base in microseconds: auto timeInMicroSec = std::chrono::duration_cast<std::chrono::microseconds>(duration); How can I format timeInMicroSec like ss::ms::us ? One can use something like: #include <iomanip> #include <sstream> //... auto c(timeInMicroSec.count()); std::ostringstream oss; oss << std::setfill('0') // set field

I come here to ask for a fix to a situation that has been frustrating me. A lot. First of all, I'm on Windows, I use MinGW as a compiler (C++). I've been having some problems with getting a program to work with the use of cpp-netlib and SSL (trying to POST to a https site). I believe everything is in order except this one error that keeps evading me. C:\boost_1_50_0\boost_1_50_0\stage\lib\libboost_thread-mgw46-mt-1_50.a(thread.o):thread.cpp|| undefined reference to 'boost::chrono::system_clock::now()' I'm sure that I've linked to chrono, as well as all the .a libs in BOOST_ROOT/stage/lib . I

I'm aware that the default value of a std::chrono::system_clock::time_point is the clock's epoch, but I can't find any mandate in the C++11 standard that system_clock 's epoch is the same as the POSIX epoch (1970-01-01T00:00:00Z). Is it safe to assume on Linux and Windows that this is the case? Or would it be smarter to use std::chrono::system_clock::from_time_t(0) ? The standard leaves the epoch of std::chrono::system_clock::time_point unspecified. There are three implementations of std::chrono::system_clock::time_point I am aware of: libc++ libstdc++ VS All three of these are thin wrappers

I am having an interesting, yet strange issue with my game timer. It seems like the milliseconds works just fine. However, when I try to apply the std::chrono::seconds cast I suddenly get 0.000000 when casting to a float. My timer is as follows: #include <iostream> #include <time.h> #include <chrono> class Timer { public: typedef std::chrono::high_resolution_clock Time; typedef std::chrono::milliseconds ms; //<--If changed to seconds, I get 0.00000 typedef std::chrono::duration<float> fsec; std::chrono::high_resolution_clock::time_point m_timestamp; float currentElapsed; Timer() { m_timestamp