std::chrono::duration<Rep,Period>::max

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< cpp‎ | chrono‎ | duration
 
 
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static constexpr duration max();
(until C++20)
static constexpr duration max() noexcept;
(since C++20)

Returns a duration with the largest possible value.

If the representation rep of the duration requires some other implementation to return a maximum-length duration, std::chrono::duration_values can be specialized to return the desired value.

Parameters

(none)

Return value

returns duration(std::chrono::duration_values<rep>::max())

Example

#include <chrono>
#include <iostream>
#include <iomanip>
#include <cstdint>
 
int main()
{
    constexpr uint64_t chrono_years_max = std::chrono::years::max().count();
    constexpr uint64_t chrono_seconds_max = std::chrono::seconds::max().count();
 
    constexpr uint64_t age_of_universe_in_years{13'787'000'000}; //: λCDM ≈ k₁/H₀ = k₂/42.
    constexpr uint64_t seconds_per_year{365'25 * 24 * 36}; // 365¼ × 24 × 60 × 60
    constexpr uint64_t age_of_universe_in_seconds{age_of_universe_in_years * seconds_per_year};
 
    std::cout 
        << "The Age of the Universe is ≈ "
        << std::scientific << std::setprecision(2)
        << static_cast<double>(age_of_universe_in_years) << " years or "
        << static_cast<double>(age_of_universe_in_seconds) << " seconds.\n\n"
        << "chrono::years::max() = " << chrono_years_max << ", sizeof(chrono::years) = "
        << sizeof(std::chrono::years) << " bytes.\n" "chrono::years "
        << (age_of_universe_in_years <= chrono_years_max ? "CAN" : "CANNOT")
        << " keep the Age of the Universe in YEARS.\n\n"
        << "chrono::seconds::max() = " << chrono_seconds_max << ", sizeof(chrono::seconds) = "
        << sizeof(std::chrono::seconds) << " bytes.\n" "chrono::seconds "
        << (age_of_universe_in_seconds <= chrono_seconds_max ? "CAN" : "CANNOT")
        << " keep the Age of the Universe in SECONDS.\n";
}

Possible output:

The Age of the Universe is ≈ 1.38e+10 years or 4.35e+17 seconds.
 
chrono::years::max() = 2147483647, sizeof(chrono::years) = 4 bytes.
chrono::years CANNOT keep the Age of the Universe in YEARS.
 
chrono::seconds::max() = 9223372036854775807, sizeof(chrono::seconds) = 8 bytes.
chrono::seconds CAN keep the Age of the Universe in SECONDS.

See also

[static]
returns the special duration value zero
(public static member function)
[static]
returns the special duration value min
(public static member function)