Test of system clocks resolution

CMakeLists.txt

cmake_minimum_required(VERSION 3.5)
project(time_res_check)
set(CMAKE_CXX_STANDARD 11)
add_executable(${PROJECT_NAME} ${PROJECT_NAME}.cpp)

time_res_check.cpp

#include <chrono>
#include <ctime>
#include <iostream>

void print_posix_resolution(clockid_t clockid)
{
    struct timespec res;
    res.tv_sec = 0;
    res.tv_nsec = 0;
    
    int retVal;
    
    retVal = clock_getres(clockid, &res);
    int errsv = errno;
    std::cerr << "    clock_getres return value: " << retVal << " with errno " << errsv  << ", " << std::endl;
    std::cerr << "    resolution: " << res.tv_nsec << " nanoseconds." << std::endl;
}

template<typename T>
void print_cxx11_resolution()
{
    double secToNano = 1e9;
    
    double periodInNs = secToNano*((double)T::num)/((double)T::den);
    std::cerr << "    resolution: " << periodInNs << " nanoseconds." << std::endl;
}

int main(int argc, char **argv) 
{
    std::cerr << "--> Testing POSIX APIs" << std::endl; 
    std::cerr << "    Error macros values: " << std::endl;
    std::cerr << "    EINTR : " << EINTR  << std::endl;
    std::cerr << "    EINVAL: " << EINVAL << std::endl;
    std::cerr << "    ENOTSUP: " << ENOTSUP << std::endl;
    std::cerr << "    Testing CLOCK_MONOTONIC " << std::endl;
    print_posix_resolution(CLOCK_MONOTONIC);
    std::cerr << "    Testing CLOCK_REALTIME " << std::endl;
    print_posix_resolution(CLOCK_REALTIME);
    std::cerr << "    Testing CLOCK_PROCESS_CPUTIME_ID " << std::endl;
    print_posix_resolution(CLOCK_PROCESS_CPUTIME_ID);
    std::cerr << "    Testing CLOCK_THREAD_CPUTIME_ID  " << std::endl;
    print_posix_resolution(CLOCK_THREAD_CPUTIME_ID );
    std::cerr << "--> Testing C++ APIs" << std::endl; 
    std::cerr << "    Testing std::chrono::high_resolution_clock " << std::endl;
    print_cxx11_resolution<std::chrono::high_resolution_clock::period>();
    std::cerr << "    Testing std::chrono::system_clock " << std::endl;
    print_cxx11_resolution<std::chrono::system_clock::period>();
    std::cerr << "    Testing std::chrono::steady_clock " << std::endl;
    print_cxx11_resolution<std::chrono::steady_clock::period>();

    
    return 0;
}