< cpp‎ | chrono‎ | duration
Utilities library
Language support
Type support (basic types, RTTI)
Library feature-test macros (C++20)
Dynamic memory management
Program utilities
Coroutine support (C++20)
Variadic functions
Debugging support
Three-way comparison
General utilities
Date and time
Function objects
Formatting library (C++20)
Relational operators (deprecated in C++20)
Integer comparison functions
Swap and type operations
Common vocabulary types
Elementary string conversions

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

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.


[edit] Parameters

d - duration to convert

[edit] Return value

d rounded up to a duration of type ToDuration.

[edit] 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;

[edit] Example

#include <chrono>
#include <iostream>
int main()
    using namespace std::chrono_literals;
    using Min = std::chrono::minutes;
        << 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";


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

[edit] See also

converts a duration to another, with a different tick interval
(function template) [edit]
converts a duration to another, rounding down
(function template) [edit]
converts a duration to another, rounding to nearest, ties to even
(function template) [edit]
converts a time_point to another, rounding up
(function template) [edit]
nearest integer not less than the given value
(function) [edit]