C++ 时间操作（获取毫秒级）【转】

古城微笑少年丶 2021-11-02 03:22 294阅读 0赞

[http://www.cnblogs.com/UnGeek/archive/2013/03/08/2950863.html][http_www.cnblogs.com_UnGeek_archive_2013_03_08_2950863.html]

//使用标准C语言的time函数，可以满足一般性需要

#include <time.h>
    #include <stdio.h>
    int main( void )
    {
        time_t t = time( 0 );
        char tmp[64];
    
        strftime( tmp, sizeof(tmp), "%Y/%m/%d %X %A 本年第%j天 %z",
        localtime(&t) );
        puts( tmp );
    
        return 0;
    }

//GetLocalTime获取当前系统时间，精确到微秒级

#include <windows.h>
    #include <stdio.h>
    
    int main( void )
    {
        SYSTEMTIME sys;
        GetLocalTime( &sys );
    
        printf( "%4d/%02d/%02d %02d:%02d:%02d.%03d 星期%1d\n"
        ,sys.wYear,sys.wMonth,sys.wDay
        ,sys.wHour,sys.wMinute,sys.wSecond,sys.wMilliseconds
        ,sys.wDayOfWeek);
    
        return 0;
    }

//利用win32 API QueryPerformanceFrequency与QueryPerformanceCounter，可以更精确精确的计算，例如拿来测试，网络抓包的精确分析

#include <windows.h>
    #include <stdio.h>
    #include <iostream>
    
    using namespace std;
    
    int main() {
        LARGE_INTEGER lv,lv_b;
    
        // 获取每秒多少CPU Performance Tick
        QueryPerformanceFrequency( &lv );
    
        // 转换为每个Tick多少秒
        double secondsPerTick = 1.0 / lv.QuadPart;
        QueryPerformanceCounter( &lv_b );
        for ( size_t i = 0; i < 100; ++i ) {
            // 获取CPU运行到现在的Tick数
            QueryPerformanceCounter( &lv );
            cout.precision( 6 );
            // 计算CPU运行到现在的时间
            // 比GetTickCount和timeGetTime更加精确
            LONGLONG duration = lv.QuadPart-lv_b.QuadPart;
            double timeElapsedTotal = secondsPerTick * duration;
            cout << fixed << showpoint << timeElapsedTotal << endl;
            //printf( "%lf \n", timeElapsedTotal ) ;
        }
        return 0;
    }

//如果上面还不能满足你的需求，请看下面

[http://www.boost.org/doc/libs/1\_53\_0/doc/html/date\_time.html][http_www.boost.org_doc_libs_1_53_0_doc_html_date_time.html]

可以提供纳秒级的精确计算，而且跨平台

转载于:https://www.cnblogs.com/Leo-Forest/p/3369340.html

[http_www.cnblogs.com_UnGeek_archive_2013_03_08_2950863.html]: http://www.cnblogs.com/UnGeek/archive/2013/03/08/2950863.html
[http_www.boost.org_doc_libs_1_53_0_doc_html_date_time.html]: http://www.boost.org/doc/libs/1_53_0/doc/html/date_time.html