std::difftime - cppreference.com (original) (raw)

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.

[edit] Parameters

[edit] Return value

Difference between two times in seconds.

[edit] 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.

[edit] Example

#include #include   int main() { std::time_t start = std::time(nullptr); volatile double d = 1.0;   // some time-consuming operation for (int p = 0; p < 10000; ++p) for (int q = 0; q < 100000; ++q) d = d + p * d * q + d;   std::cout << "Wall time passed: " << std::difftime(std::time(nullptr), start) << " s.\n"; }

Possible output:

[edit] See also