std::chrono::duration::max(3)

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)