std::chrono...ution_clock(3)

🌸 NAME 🌸

std::chrono::high_resolution_clock — std::chrono::high_resolution_clock

Okay bestie, this is the C++ Standard Libary page for std::chrono...ution_clock(3), and the NAME section is literally doubling the same name like a mirror selfie 💅. We're talking about std::chrono::high_resolution_clock, and it's kind of a main-character clock.

---

✨ Synopsis ✨

Defined in header <chrono>
class high_resolution_clock;  (since C++11)

Class std::chrono::high_resolution_clock represents the clock with the smallest tick period provided by the implementation. It may be an alias of std::chrono::system_clock or std::chrono::steady_clock, or a third, independent clock.

And yes, std::chrono::high_resolution_clock meets the requirements of TrivialClock. Slay 🫶.

---

🎀 Member types 🎀

• rep — arithmetic type representing the number of ticks in the clock's duration
• period — a std::ratio type representing the tick period of the clock, in seconds
• duration — std::chrono::duration<rep, period>
• time_point — std::chrono::time_point<std::chrono::high_resolution_clock>

---

💫 Member constants 💫

• constexpr bool is_steady [static] — true if the time between ticks is always constant, i.e. calls to now() return values that increase monotonically even in case of some external clock adjustment, otherwise false; this is a public static member constant

---

🔥 Member functions 🔥

• now [static] — returns a std::chrono::time_point representing the current value of the clock; public static member function

---

😭 Notes 😭

There has been some controversy around the use of high_resolution_clock. Howard Hinnant, who claims to have introduced high_resolution_clock to the language, stated in 2016 on the ISO C++ Standard - Discussion mailing list that he was in favor of deprecating it. His rationale was that, because the standard allows for it to be an alias for std::chrono::steady_clock or std::chrono::system_clock, its use adds uncertainty to a program without benefit. However, other participants in the thread spoke out in its favor, for instance on the basis that, because neither std::chrono::steady_clock nor std::chrono::system_clock come with any particular resolution guarantees, high_resolution_clock serves a useful role by giving the vendor an opportunity to supply the platform's highest-resolution clock, when neither its std::chrono::steady_clock nor its std::chrono::system_clock would be that.

It is often just an alias for std::chrono::steady_clock or std::chrono::system_clock, but which one it is depends on the library or configuration. When it is a system_clock, it is not monotonic (e.g., the time can go backwards). For example, as of 2023, libstdc++ has it aliased to system_clock "until higher-than-nanosecond definitions become feasible"^[1], MSVC has it as steady_clock^[2], and libc++ uses steady_clock when the C++ standard library implementation supports a monotonic clock and system_clock otherwise^[3].

Vibe check: this clock might be a total icon, or it might lowkey be wearing a system_clock disguise. Check your library, bestie 👀.

---

👑 See also 👑

• system_clock — wall clock time from the system-wide realtime clock (C++11) (class)
• steady_clock — monotonic clock that will never be adjusted (C++11) (class)

---

🌈 External links 🌈

1. ↑ libstdc++ <chrono.h>
2. ↑ msvc high_resolution_clock
3. ↑ libc++ <high_resolution_clock.h>

---

Bye bestie! This was std::chrono...ution_clock(3) from http://cppreference.com, dated 2024.06.10. Stay steady — or not, depending on your alias — periodt 💖✨