std::chrono::clock_cast(3)

💅 std::chrono::clock_cast 💅

okay bestie, so this one is a function template from the C++ Standard Library — the manual name is std::chrono::clock_cast(3), and it's literally defined in the header <chrono>. she converts time points between clocks and she does it flawlessly. ✨

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🌸 SYNOPSIS 🌸

Defined in header <chrono>:

template< class Dest, class Source, class Duration >
auto clock_cast( const std::chrono::time_point<Source, Duration>& t );

(since C++20) 🫶

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💖 DESCRIPTION 💖

So what she actually does: she takes the time point t of a clock Source and converts it into an equivalent time point of the clock Dest. And if she has to, she'll use std::chrono::system_clock and/or std::chrono::utc_clock as intermediaries — like, middlemen. no cap. 🔥

Here's the whole decision tree, and honestly the way she picks is giving main character energy:

• If the expression std::chrono::clock_time_conversion<Dest, Source>{}(t) is well-formed, she just returns the result of that expression. easy. iconic. ✨
• Otherwise, if at least one of the following two expressions is well-formed, then:
  • If both expressions are well-formed, the conversion is ambiguous, and the program is ill-formed 😭 (yes, that's a real problem, not a vibe)
  • Otherwise, exactly one of the two expressions is well-formed, and the result of that expression is returned. slay.
  1. std::chrono::clock_time_conversion<Dest, std::chrono::system_clock>{}(std::chrono::clock_time_conversion<std::chrono::system_clock, Source>{}(t))
  2. std::chrono::clock_time_conversion<Dest, std::chrono::utc_clock>{}(std::chrono::clock_time_conversion<std::chrono::utc_clock, Source>{}(t))
• Otherwise, if at least one of the following two expressions is well-formed, then:
  • If both expressions are well-formed, the conversion is ambiguous, and the program is ill-formed 💀 (again — not cute, it's a hard error)
  • Otherwise, exactly one of the two expressions is well-formed, and the result of that expression is returned. periodt.
  1. std::chrono::clock_time_conversion<Dest, std::chrono::utc_clock>{}(std::chrono::clock_time_conversion<std::chrono::utc_clock, std::chrono::system_clock>{}(std::chrono::clock_time_conversion<std::chrono::system_clock, Source>{}(t)))
  2. std::chrono::clock_time_conversion<Dest, std::chrono::system_clock>{}(std::chrono::clock_time_conversion<std::chrono::system_clock, std::chrono::utc_clock>{}(std::chrono::clock_time_conversion<std::chrono::utc_clock, Source>{}(t)))
• Otherwise, this function does not participate in overload resolution. she simply ✨ leaves ✨ 🦋

bestie listen — those "both well-formed → ambiguous → ill-formed" bits are fr fr the important part. it's not a warning, the program is simply not valid. don't be that girl. 🙈

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🎀 RETURN VALUE 🎀

The result of the conversion, determined exactly as described above. that's it, that's the tea. 🍓

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🌈 EXAMPLE 🌈

This section is incomplete.

Reason: no example 😭 (she's a mystery, iykyk)

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⭐ SEE ALSO ⭐

• clock_time_conversion — traits class defining how to convert time points of one clock to another (C++20) (class template) 👑

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🦋 CATEGORY 🦋

• Todo: no example 💀

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mwah 💜 that's the whole page — sourced from http://cppreference.com, version 2024.06.10, and the page title is std::chrono::clock_cast(3). go forth and convert your clocks, bestie. 🕰️✨