C++: How would I get unix time?

Question

I need a function or way to get the UNIX epoch in seconds, much like how I can in PHP using the time function.

I can't find any method except the time() in ctime which seems to only output a formatted date, or the clock() function which has seconds but seems to always be a multiple of 1 million, nothing with any resolution.

I wish to measure execution time in a program, I just wanted to calculate the diff between start and end; how would a C++ programmer do this?

EDIT: time() and difftime only allow resolution by seconds, not ms or anything too btw.

Do you want something better than second precision, but measured in seconds? — Brandon Yarbrough, Jun 13 '10 at 06:45
You pose unrelated requirements. You say you want unix epoch in seconds, and you say you want to measure performance/execution time. These two things are normally achieved by different means. — n. m. could be an AI, Aug 12 '18 at 01:57

score 2 · Answer 1 · edited May 23 '17 at 10:30

2

time() should work fine, use difftime for difference of time calculations. In case you need better resolutuion, use gettimeofday.

Also, duplicate of: Calculating elapsed time in a C program in milliseconds

edited May 23 '17 at 10:30

Community

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answered Jun 13 '10 at 06:40

Drakosha

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R Samuel Klatchko · Answer 2 · 2010-06-13T07:02:41.493

2

If you want to profile get, I'd recommend using getrusage. This will allow you to track CPU time instead of wall clock time:

struct rusage ru;
getrusage(RUSAGE_SELF, &ru);

ru.ru_utime.tv_sec;  // seconds of user CPU time
ru.ru_utime.tv_usec; // microseconds of user CPU time
ru.ru_stime.tv_sec;  // seconds of system CPU time
ru.ru_stime.tv_usec; // microseconds of system CPU time

edited Jun 13 '10 at 07:02

answered Jun 13 '10 at 06:49

R Samuel Klatchko

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score 0 · Answer 3 · answered Aug 12 '18 at 01:53

This code should work for you.

time_t epoch = time(0);

#include <iostream>
#include <ctime>
using namespace std;

int main() {
    time_t time = time(0);
    cout<<time<<endl;
    system("pause");
    return 0;
}

If you have any questions, feel free to comment below.

C++: How would I get unix time?

3 Answers3