std::timespec

From cppreference.com
< cpp‎ | chrono‎ | c
C++
Date and time library
Time point
(C++11)
(C++20)
Duration
(C++11)
Clocks
(C++11)
(C++11)
(C++20)
(C++20)
(C++20)
(C++11)
(C++20)
(C++20)
(C++20)
Time of day
(C++20)(C++20)
(C++20)(C++20)
(C++20)

Calendar
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)(C++20)
Time zone
(C++20)
(C++20)
(C++20) (C++20) (C++20) (C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
chrono I/O
(C++20)
C-style date and time
C-style date and time utilities
Functions
Time manipulation
(C++17)
Format conversions
Constants
Types
timespec
(C++17)
Defined in header <ctime>
struct timespec;
 (since C++17)

Structure holding an interval broken down into seconds and nanoseconds.

Data members

Member Description
whole seconds, the value is >= ​0​
(public member object)
long tv_nsec
 nanoseconds, the value is in range [ ​0​ ,  999999999 ]
(public member object)

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

(C++17)
 returns the calendar time in seconds and nanoseconds based on a given time base
(function)
calendar time type
(class)
C documentation for timespec
Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/chrono/c/timespec&oldid=180252