NAME¶

std::chrono::duration::max - std::chrono::duration::max

Synopsis¶

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¶

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

Example¶

// Run this code

#include <chrono>
#include <cstdint>
#include <iomanip>
#include <iostream>

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}; // Λ-CDM ≈ 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
<< std::scientific << std::setprecision(2)
<< "The Age of the Universe is ≈ "
<< 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¶

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