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测量时间差

发布于 2024-10-08 03:20:11 字数 110 浏览 3 评论 0原文

我想以毫秒为单位测量启动应用程序与另一个时间（例如 16:00 点）之间的时间间隔。最好的方法是什么？

我查看了“时钟”功能，但这不是我需要的。

操作系统：Win NT及以上

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你另情深 2024-10-15 03:20:11

查找 POSIX 系统的 gettimeofday ，以及 timeGetTime（适用于 Windows）。

编辑：OP似乎要求提供代码来将当前时间/日期与另一个时间/日期进行比较。以下代码片段演示了如何在 Windows 上获取当前日期和时间：

 #include ;
 #include ;

 无效主（）
 {
     系统时间st；
     获取系统时间(&st);
     printf("年:%d\n月:%d\n日期:%d\n小时:%d\n分钟:%d\n秒:%d\n"
       ,st.w年,st.w月,st.w日,st.w小时,st.w分,st.w秒);
 }

下面是如何计算两个 SYSTEMTIME 对象之间的差异：

 #include ;
 #include ;

 // 返回时间差，单位为 100 us。
 _int64 Delta(const SYSTEMTIME st1, const SYSTEMTIME st2) {
  联合时间联合 {
      FILETIME 文件时间；
      ULARGE_INTEGER ul；
  };

  时间联盟 ft1；
  时间联盟 ft2；

  SystemTimeToFileTime(&st1, &ft1.fileTime);
  SystemTimeToFileTime(&st2, &ft2.fileTime);

  返回 ft2.ul.QuadPart - ft1.ul.QuadPart；
}

int main() {
  系统时间 t1 = {0}，t2 = {0}；
  t1.wDay = 10;
  t1.wMonth = 4;
  t1.wYear = 2009;

  t2.wDay = 12;
  t2.wMonth = 4;
  t2.wYear = 2009;

  _int64 i = Delta(t1, t2);
  std::cout << “时间是”<< i / 10000000 << " 相隔几秒\n";

  返回0；
}

这两个示例应该为您提供完成您需要的工具。

Look up gettimeofday for POSIX systems, and timeGetTime for Windows.

Edit: Seems the OP was asking for code to compare current time/date against another time/date. The following snippet demonstrates how to get current date and time on Windows:

 #include <Windows.h>
 #include <stdio.h>

 void main()
 {
     SYSTEMTIME st;
     GetSystemTime(&st);
     printf("Year:%d\nMonth:%d\nDate:%d\nHour:%d\nMin:%d\nSecond:%d\n"
       ,st.wYear,st.wMonth,st.wDay,st.wHour,st.wMinute,st.wSecond);
 }

And here's how to compute the difference between two SYSTEMTIME objects:

 #include <windows.h>
 #include <iostream>

 // Return time difference in units of 100 us.
 _int64 Delta(const SYSTEMTIME st1, const SYSTEMTIME st2) {
  union timeunion {
      FILETIME fileTime;
      ULARGE_INTEGER ul;
  } ;

  timeunion ft1;
  timeunion ft2;

  SystemTimeToFileTime(&st1, &ft1.fileTime);
  SystemTimeToFileTime(&st2, &ft2.fileTime);

  return ft2.ul.QuadPart - ft1.ul.QuadPart;
}

int main() {
  SYSTEMTIME t1 = {0}, t2 = {0};
  t1.wDay = 10;
  t1.wMonth = 4;
  t1.wYear = 2009;

  t2.wDay = 12;
  t2.wMonth = 4;
  t2.wYear = 2009;

  _int64 i = Delta(t1, t2);
  std::cout << "times are " << i / 10000000 << " seconds apart\n";

  return 0;
}

Those two samples should give you the tools to do what you need.

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篱下浅笙歌 2024-10-15 03:20:11

如果您使用的是 POSIX 系统，则可以使用 gettimeofday(3) ：

struct timeval start, end;
gettimeofday(&start, NULL);
...
gettimeofday(&end, NULL);

// Watch out for overflow!
int delta_milliseconds = 1000 * (end.tv_sec - start.tv_sec) + (end.tv_usec - start.tv_usec)/1000;

如果您使用的是 Windows，则可以使用 GetTickCount：

DWORD start, end;
start = GetTickCount();
...
end = GetTickCount();
int delta_milliseconds = end - start;

但是要注意 GetTickCount 的分辨率只有大约 10-16 毫秒。如果您需要更高的精度，请使用 QueryPerformanceCounter 和 QueryPerformanceFrequency 相反：

// Error-checking omitted for expository purposes
LARGE_INTEGER freq, start, end;
QueryPerformanceFrequency(&freq);
QueryPerformanceCounter(&start);
...
QueryPerformanceCounter(&end);
double delta_milliseconds = (double)(end.QuadPart - start.QuadPart) / freq.QuadPart * 1000.0;

If you're on a POSIX system, you can use gettimeofday(3):

struct timeval start, end;
gettimeofday(&start, NULL);
...
gettimeofday(&end, NULL);

// Watch out for overflow!
int delta_milliseconds = 1000 * (end.tv_sec - start.tv_sec) + (end.tv_usec - start.tv_usec)/1000;

If you're on Windows, you can use GetTickCount:

DWORD start, end;
start = GetTickCount();
...
end = GetTickCount();
int delta_milliseconds = end - start;

But but aware that GetTickCount only has a resolution of about 10-16 ms. If you need more precision, use QueryPerformanceCounter and QueryPerformanceFrequency instead:

// Error-checking omitted for expository purposes
LARGE_INTEGER freq, start, end;
QueryPerformanceFrequency(&freq);
QueryPerformanceCounter(&start);
...
QueryPerformanceCounter(&end);
double delta_milliseconds = (double)(end.QuadPart - start.QuadPart) / freq.QuadPart * 1000.0;

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~没有更多了~