std::chrono...::duration)(3)

💖 NAME 💖

okay bestie, welcome to the std::chrono...::duration)(3) page from the C++ Standard Libary (yes, that’s how it’s spelled on the page 😭). We’re here for std::chrono::ceil(std::chrono::duration) — and the NAME literally says std::chrono::ceil(std::chrono::duration) twice, because it understood the assignment 💅✨

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🌸 Synopsis 🌸

Defined in header <chrono> 🫶

template< class ToDuration, class Rep, class Period >
constexpr ToDuration ceil( const std::chrono::duration<Rep, Period>&
d );

(since C++17) — periodt, this one is living its C++17 era ⭐

Returns the smallest duration t representable in ToDuration that is greater or equal to d. Not me being dramatic, that’s literally the whole point 😌

Vibe check: the function does not participate in the overload resolution unless ToDuration is a specialization of std::chrono::duration. So if your type isn’t giving duration energy, it’s not invited to the overload party 🙈

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🫶 Parameters 🫶

• d — duration to convert

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🌈 Return value 🌈

d rounded up to a duration of type ToDuration. slay 💖

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🧚 Possible implementation 🧚

bestie, if you wanna peek behind the curtain, here’s the possible implementation, copied with love and zero gatekeeping:

namespace detail
{
    template<class> inline constexpr bool is_duration_v = false;
    template<class Rep, class Period> inline constexpr bool is_duration_v<
        std::chrono::duration<Rep, Period>> = true;
}

template<class To, class Rep, class Period,
         class = std::enable_if_t<detail::is_duration_v<To>>>
constexpr To ceil(const std::chrono::duration<Rep, Period>& d)
{
    To t = std::chrono::duration_cast<To>(d);
    if (t < d)
        return t + To{1};
    return t;
}

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🍓 Example 🍓

// Run this code — that’s what the page says, so go off 👑

#include <chrono>
#include <iostream>

int main()
{
    using namespace std::chrono_literals;
    using Min = std::chrono::minutes;

    std::cout
        << std::showpos
        << "ceil(+2.4min) = " << std::chrono::ceil<Min>(+2.4min).count() << "min\n"
        << "ceil(-2.4min) = " << std::chrono::ceil<Min>(-2.4min).count() << "min\n"
        << "ceil(+0.0min) = " << std::chrono::ceil<Min>(+0.0min).count() << "min\n";
}

🎀 Output 🎀

ceil(+2.4min) = +3min
ceil(-2.4min) = -2min
ceil(+0.0min) = +0min

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👑 See also 👑

• duration_cast — converts a duration to another, with a different tick interval (C++11) (function template).
• floor(std::chrono::duration) — converts a duration to another, rounding down (C++17) (function template).
• round(std::chrono::duration) — converts a duration to another, rounding to nearest, ties to even (C++17) (function template).
• ceil(std::chrono::time_point) — converts a time_point to another, rounding up (C++17) (function template).
• ceil, ceilf, ceill — nearest integer not less than the given value (function) (C++11) (C++11).

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and that’s the page, bestie! footer sign-off time: source http://cppreference.com, date/version 2024.06.10, title std::chrono...::duration)(3) — mwah, go round up your durations 💅✨💖