C++时间处理1-获取当前时间戳

// for Unix-like system
#include <sys/time.h>

uint64_t timestamp_us()
{
    struct timeval t;
    gettimeofday(&t, 0);
    return (uint64_t)(t.tv_sec * 1000000ULL + t.tv_usec);
}

#include <cstdint>

/**
     * @brief Time unit enum.
     *
     */
    enum class timeunit
    {
        /** second */
        s,
        /** millisecond */
        ms,
        /** microsecond */
        us,
    };

    /**
     * @brief Get current timestamp.
     *
     * @param unit time unit
     * @return uint64_t timestamp
     */
    uint64_t timestamp(timeunit unit);

#include "timeutil.h"
#include <chrono>

uint64_t timestamp(timeunit unit)
{
    // for C++11 and later
    auto now = std::chrono::system_clock::now();
    auto timestamp_ms = std::chrono::duration_cast<std::chrono::microseconds>(now.time_since_epoch()).count();
    auto us = static_cast<uint64_t>(timestamp_ms);
    uint64_t t = 0;
    switch (unit)
    {
    case timeunit::s:
        t = us2s(us);
        break;
    case timeunit::ms:
        t = us2ms(us);
        break;
    case timeunit::us:
        t = us;
        break;
    default:
        break;
    }
    return t;
}

#include "timeutil.h"
#include "common.hpp"

void TestTimestamp()
{
    PrintSubTitle("TestTimestamp");

    std::cout << "current timestamp( s): " << cutl::timestamp(cutl::timeunit::s) << std::endl;
    std::cout << "current timestamp(ms): " << cutl::timestamp(cutl::timeunit::ms) << std::endl;
    std::cout << "current timestamp(us): " << cutl::timestamp(cutl::timeunit::us) << std::endl;
}