C++ Cross-Platform High-Resolution Timer

Question

I\'m looking to implement a simple timer mechanism in C++. The code should work in Windows and Linux. The resolution should be as precise as possible (at least millisecond a

Answer 1

Late to the party here, but I'm working in a legacy codebase that can't be upgraded to c++11 yet. Nobody on our team is very skilled in c++, so adding a library like STL is proving difficult (on top of potential concerns others have raised about deployment issues). I really needed an extremely simple cross platform timer that could live by itself without anything beyond bare-bones standard system libraries. Here's what I found:

http://www.songho.ca/misc/timer/timer.html

Reposting the entire source here just so it doesn't get lost if the site ever dies:

    //////////////////////////////////////////////////////////////////////////////
// Timer.cpp
// =========
// High Resolution Timer.
// This timer is able to measure the elapsed time with 1 micro-second accuracy
// in both Windows, Linux and Unix system 
//
//  AUTHOR: Song Ho Ahn (song.ahn@gmail.com) - http://www.songho.ca/misc/timer/timer.html
// CREATED: 2003-01-13
// UPDATED: 2017-03-30
//
// Copyright (c) 2003 Song Ho Ahn
//////////////////////////////////////////////////////////////////////////////

#include "Timer.h"
#include 

///////////////////////////////////////////////////////////////////////////////
// constructor
///////////////////////////////////////////////////////////////////////////////
Timer::Timer()
{
#if defined(WIN32) || defined(_WIN32)
    QueryPerformanceFrequency(&frequency);
    startCount.QuadPart = 0;
    endCount.QuadPart = 0;
#else
    startCount.tv_sec = startCount.tv_usec = 0;
    endCount.tv_sec = endCount.tv_usec = 0;
#endif

    stopped = 0;
    startTimeInMicroSec = 0;
    endTimeInMicroSec = 0;
}



///////////////////////////////////////////////////////////////////////////////
// distructor
///////////////////////////////////////////////////////////////////////////////
Timer::~Timer()
{
}



///////////////////////////////////////////////////////////////////////////////
// start timer.
// startCount will be set at this point.
///////////////////////////////////////////////////////////////////////////////
void Timer::start()
{
    stopped = 0; // reset stop flag
#if defined(WIN32) || defined(_WIN32)
    QueryPerformanceCounter(&startCount);
#else
    gettimeofday(&startCount, NULL);
#endif
}



///////////////////////////////////////////////////////////////////////////////
// stop the timer.
// endCount will be set at this point.
///////////////////////////////////////////////////////////////////////////////
void Timer::stop()
{
    stopped = 1; // set timer stopped flag

#if defined(WIN32) || defined(_WIN32)
    QueryPerformanceCounter(&endCount);
#else
    gettimeofday(&endCount, NULL);
#endif
}



///////////////////////////////////////////////////////////////////////////////
// compute elapsed time in micro-second resolution.
// other getElapsedTime will call this first, then convert to correspond resolution.
///////////////////////////////////////////////////////////////////////////////
double Timer::getElapsedTimeInMicroSec()
{
#if defined(WIN32) || defined(_WIN32)
    if(!stopped)
        QueryPerformanceCounter(&endCount);

    startTimeInMicroSec = startCount.QuadPart * (1000000.0 / frequency.QuadPart);
    endTimeInMicroSec = endCount.QuadPart * (1000000.0 / frequency.QuadPart);
#else
    if(!stopped)
        gettimeofday(&endCount, NULL);

    startTimeInMicroSec = (startCount.tv_sec * 1000000.0) + startCount.tv_usec;
    endTimeInMicroSec = (endCount.tv_sec * 1000000.0) + endCount.tv_usec;
#endif

    return endTimeInMicroSec - startTimeInMicroSec;
}



///////////////////////////////////////////////////////////////////////////////
// divide elapsedTimeInMicroSec by 1000
///////////////////////////////////////////////////////////////////////////////
double Timer::getElapsedTimeInMilliSec()
{
    return this->getElapsedTimeInMicroSec() * 0.001;
}



///////////////////////////////////////////////////////////////////////////////
// divide elapsedTimeInMicroSec by 1000000
///////////////////////////////////////////////////////////////////////////////
double Timer::getElapsedTimeInSec()
{
    return this->getElapsedTimeInMicroSec() * 0.000001;
}



///////////////////////////////////////////////////////////////////////////////
// same as getElapsedTimeInSec()
///////////////////////////////////////////////////////////////////////////////
double Timer::getElapsedTime()
{
    return this->getElapsedTimeInSec();
}

and the header file:

//////////////////////////////////////////////////////////////////////////////
// Timer.h
// =======
// High Resolution Timer.
// This timer is able to measure the elapsed time with 1 micro-second accuracy
// in both Windows, Linux and Unix system 
//
//  AUTHOR: Song Ho Ahn (song.ahn@gmail.com) - http://www.songho.ca/misc/timer/timer.html
// CREATED: 2003-01-13
// UPDATED: 2017-03-30
//
// Copyright (c) 2003 Song Ho Ahn
//////////////////////////////////////////////////////////////////////////////

#ifndef TIMER_H_DEF
#define TIMER_H_DEF

#if defined(WIN32) || defined(_WIN32)   // Windows system specific
#include 
#else          // Unix based system specific
#include 
#endif


class Timer
{
public:
    Timer();                                    // default constructor
    ~Timer();                                   // default destructor

    void   start();                             // start timer
    void   stop();                              // stop the timer
    double getElapsedTime();                    // get elapsed time in second
    double getElapsedTimeInSec();               // get elapsed time in second (same as getElapsedTime)
    double getElapsedTimeInMilliSec();          // get elapsed time in milli-second
    double getElapsedTimeInMicroSec();          // get elapsed time in micro-second


protected:


private:
    double startTimeInMicroSec;                 // starting time in micro-second
    double endTimeInMicroSec;                   // ending time in micro-second
    int    stopped;                             // stop flag 
#if defined(WIN32) || defined(_WIN32)
    LARGE_INTEGER frequency;                    // ticks per second
    LARGE_INTEGER startCount;                   //
    LARGE_INTEGER endCount;                     //
#else
    timeval startCount;                         //
    timeval endCount;                           //
#endif
};

#endif // TIMER_H_DEF