std::difftime

Defined in header <ctime>

1	`double` `difftime( std::time_t` `time_end, std::time_t` `time_beg );`

Computes difference between two calendar times as std::time_t objects (time_end - time_beg) in seconds. If time_end refers to time point before time_beg then the result is negative.

Parameters

time_beg, time_end

times to compare

Return value

Difference between two times in seconds.

Notes

On POSIX systems, std::time_t is measured in seconds, and difftime is equivalent to arithmetic subtraction, but C and C++ allow fractional units for time_t.

Example

#include <iostream>
#include <ctime>
  
int main()
{
    std::time_t start = std::time(NULL);
    volatile double d;
  
    // some time-consuming operation
    for (int n=0; n<10000; ++n) {
        for (int m=0; m<100000; ++m) {
           d += d*n*m;
        }
    }
  
    std::cout << "Wall time passed: "
              << std::difftime(std::time(NULL), start) << " s.\n";
}

Output:

1	`Wall` `time` `passed: 7 s.`

duration (C++11)	a time interval (class template)
C documentation for `difftime`

std::difftime

Parameters

Return value

Notes

Example

See also