MISRA and AUTOSAR do not allow us to use the time() function of <ctime> (and <time.h>).
Rule 18-0-4: The time handling functions of library
<ctime>shall not be used.
Is there an alternative to the time() function in C++?
There is the time library <chrono>. But there I didn't find a function that returns the current time like time(). Or am I missing something?
Using the <chrono> header requires a little more involvement than the time function.
You can create a time_point using std::chrono::steady_clock::now(). Subtracting two time_point instances creates a std::duration which reflects the difference in time between the two instances. You can then use a duration_cast to cast this duration to a scale of your choice (microsecond, millisecond etc.) and then use the count member function to get the actual time in unsigned type.
TL;DR You can measure elapsed time between two events by doing this:
const auto start = std::chrono::steady_clock::now(); // event 1
// something happens in between...
const auto end = std::chrono::steady_clock::now(); // event 2
const auto time_elapsed = std::chrono::duration_cast<std::chrono::microseconds>(end-start).count();
Notes:
time_elapsed is not a floating-point variable,std::chrono::steady_clock should be preferred to std::chrono::system_clock because the former is a monotonic clock i.e. it will not be adjusted by the OS.