C++获取当前系统时间并转为，年月日时分秒毫秒的格式

#include <iostream>
#include <string>

#include <chrono>
#include <ctime>
#include <iomanip>
#include <sstream>
using namespace std;
 
string get_cur_time_mm() {
    cout << "get cur time mm" << endl;
    auto tNow     = std::chrono::system_clock::now();
    auto tSeconds = std::chrono::duration_cast<std::chrono::seconds>(tNow.time_since_epoch());
    auto tMilli   = std::chrono::duration_cast<std::chrono::milliseconds>(tNow.time_since_epoch());
    auto ms       = tMilli - tSeconds;

    time_t timep;
    time(&timep); /*获得time_t结构的时间，UTC时间*/
    tm*                localt = localtime(&timep);
    std::ostringstream oss;
    oss << put_time(localt, "%Y%m%d%H%M%S");
    oss << std::setfill('0') << std::setw(3) << ms.count();
    return oss.str();
}