Microtime()等价于C和c++吗?

I am wondering if there is an equivalent to the PHP function microtime() in C and C++. I looked around but couldn't find a definitive answer.

我想知道在C和c++中是否有一个等价于PHP函数microtime()的函数。我环顾四周，却找不到一个明确的答案。

Thanks!

谢谢!

5 个解决方案

#1

On Linux, you can use gettimeofday, which should give the same information. In fact, I believe that is the function that PHP uses under the covers.

在Linux上，您可以使用gettimeofday，它应该提供相同的信息。事实上，我相信这是PHP在幕后使用的函数。

#2

There is no exact equivalent to PHP's microtime(), but you could a function with a similar functionality based on the following code:

与PHP的microtime()没有完全相同的功能，但是您可以使用基于以下代码的类似功能的函数:

Mac OS X and probably also Linux/Unix

#include <sys/time.h>
struct timeval time;
gettimeofday(&time, NULL); #This actually returns a struct that has microsecond precision.
long microsec = ((unsigned long long)time.tv_sec * 1000000) + time.tv_usec;

(based on: http://brian.pontarelli.com/2009/01/05/getting-the-current-system-time-in-milliseconds-with-c/)

(基于:http://brian.pontarelli.com/2009/01/05/getting-the-current-system-time-in-milliseconds-with-c/)

---

Windows:

unsigned __int64 freq;
QueryPerformanceFrequency((LARGE_INTEGER*)&freq);
double timerFrequency = (1.0/freq);

unsigned __int64 startTime;
QueryPerformanceCounter((LARGE_INTEGER *)&startTime);

//do something...

unsigned __int64 endTime;
QueryPerformanceCounter((LARGE_INTEGER *)&endTime);
double timeDifferenceInMilliseconds = ((endTime-startTime) * timerFrequency);

(answer by Darcara, from: https://*.com/a/4568649/330067)

(达卡拉回答:https://*.com/a/4568649/330067)

#3

C++11 added some standard timekeeping functions (see section 20.11 "Time utilities") with good accuracy, but most compilers don't support those yet.

c++ 11增加了一些标准的计时功能(参见20.11节“时间实用程序”)，非常准确，但是大多数编译器还不支持这些功能。

Mostly you need to use your OS API, such as gettimeofday for POSIX.

大多数情况下，您需要使用OS API，比如POSIX的gettimeofday。

#4

For timing sections of code, try std::clock, which returns ticks, then divide by CLOCKS_PER_SEC.

对于代码的计时段，请尝试std::clock，它返回节拍，然后除以CLOCKS_PER_SEC。

#5

libUTP (uTorrent Transport Protocol library) has a good example on getting the microtime on different platforms.

libUTP (uTorrent传输协议库)是在不同平台上获得微时间的一个很好的例子。