NAME¶

std::chrono::ceil(std::chrono::duration) - std::chrono::ceil(std::chrono::duration)

Synopsis¶

Defined in header <chrono>
template <class ToDuration, class Rep, class Period>
constexpr ToDuration ceil(const std::chrono::duration<Rep, Period>& (since C++17)
d);

Returns the smallest duration t representable in ToDuration that is greater or equal
to d.

The function does not participate in the overload resolution unless ToDuration is a
specialization of std::chrono::duration.

Parameters¶

d - duration to convert

Return value¶

d rounded up to a duration of type ToDuration.

Possible implementation¶

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;
}

Example¶

// Run this code

#include <iostream>
#include <chrono>

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

See also¶

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