Timer function to provide time in nano seconds using C++

Question

I wish to calculate the time it took for an API to return a value. The time taken for such an action is in the space of nano seconds. As the API is a C++ class/function, I a

Answer 1

Here is a nice Boost timer that works well:

//Stopwatch.hpp

#ifndef STOPWATCH_HPP
#define STOPWATCH_HPP

//Boost
#include 
//Std
#include 

class Stopwatch
{
public:
    Stopwatch();
    virtual         ~Stopwatch();
    void            Restart();
    std::uint64_t   Get_elapsed_ns();
    std::uint64_t   Get_elapsed_us();
    std::uint64_t   Get_elapsed_ms();
    std::uint64_t   Get_elapsed_s();
private:
    boost::chrono::high_resolution_clock::time_point _start_time;
};

#endif // STOPWATCH_HPP


//Stopwatch.cpp

#include "Stopwatch.hpp"

Stopwatch::Stopwatch():
    _start_time(boost::chrono::high_resolution_clock::now()) {}

Stopwatch::~Stopwatch() {}

void Stopwatch::Restart()
{
    _start_time = boost::chrono::high_resolution_clock::now();
}

std::uint64_t Stopwatch::Get_elapsed_ns()
{
    boost::chrono::nanoseconds nano_s = boost::chrono::duration_cast(boost::chrono::high_resolution_clock::now() - _start_time);
    return static_cast(nano_s.count());
}

std::uint64_t Stopwatch::Get_elapsed_us()
{
    boost::chrono::microseconds micro_s = boost::chrono::duration_cast(boost::chrono::high_resolution_clock::now() - _start_time);
    return static_cast(micro_s.count());
}

std::uint64_t Stopwatch::Get_elapsed_ms()
{
    boost::chrono::milliseconds milli_s = boost::chrono::duration_cast(boost::chrono::high_resolution_clock::now() - _start_time);
    return static_cast(milli_s.count());
}

std::uint64_t Stopwatch::Get_elapsed_s()
{
    boost::chrono::seconds sec = boost::chrono::duration_cast(boost::chrono::high_resolution_clock::now() - _start_time);
    return static_cast(sec.count());
}