std::timespec

 

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C-style date and time

 

C-style date and time utilities

Functions

Time manipulation

difftime

time

clock

timespec_get (C++17)

Format conversions

asctime

ctime

strftime

wcsftime

gmtime

localtime

mktime

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CLOCKS_PER_SEC

Types

tm

time_t

clock_t

timespec (C++17)

 

Defined in header <ctime>
struct timespec;		(since C++17)

Structure holding an interval broken down into seconds and nanoseconds.

Member objects

std::time_t tv_sec	whole seconds – >= 0
long tv_nsec	nanoseconds – [​0​, 999999999]

The declaration order of tv_sec and tv_nsec is unspecified. Implementation may add other data members to timespec.

Notes

The type of tv_nsec is long long on some platforms, which is currently non-conforming in C++, but is allowed in C since C23.

Example

Run this code

#include <ctime>
#include <iostream>
 
int main()
{
    std::timespec ts;
    std::timespec_get(&ts, TIME_UTC);
    char buff[0x80];
    std::strftime(buff, sizeof buff, "%D %T", std::gmtime(&ts.tv_sec));
 
//  auto [sec, nsec] = ts; // UB: structured bindings should not be used because the
                           // declaration order and data member list are unspecified
 
    std::cout << "Current time: " << buff << " (UTC)\n"
              << "Raw timespec.tv_sec: " << ts.tv_sec << '\n'
              << "Raw timespec.tv_nsec: " << ts.tv_nsec << '\n';
}

Possible output:

Current time: 04/06/23 12:03:31 (UTC)
Raw timespec.tv_sec: 1680782611
Raw timespec.tv_nsec: 678437213

See also

timespec_get (C++17)	returns the calendar time in seconds and nanoseconds based on a given time base (function)
tm	calendar time type (class)
C documentation for timespec