[time.duration.literals]

If any of these suffixes are applied to a floating-point-literal the result is a chrono::duration literal with an unspecified floating-point representation.

If any of these suffixes are applied to an integer-literal and the resulting chrono::duration value cannot be represented in the result type because of overflow, the program is ill-formed.

[Example 1:

The following code shows some duration literals.

using namespace std::chrono_literals; auto constexpr aday=24h; auto constexpr lesson=45min; auto constexpr halfanhour=0.5h; — end example]

🔗

constexpr chrono::hours                                 operator""h(unsigned long hours);
constexpr chrono::duration<unspecified, ratio<3600, 1> operator""h(long double hours);

Returns: A duration literal representing hours hours.

🔗

constexpr chrono::minutes                             operator""min(unsigned long minutes);
constexpr chrono::duration<unspecified, ratio<60, 1> operator""min(long double minutes);

Returns: A duration literal representing minutes minutes.

🔗

constexpr chrono::seconds               operator""s(unsigned long sec);
constexpr chrono::duration<unspecified> operator""s(long double sec);

[Note 1:

The same suffix s is used for basic_string but there is no conflict, since duration suffixes apply to numbers and string literal suffixes apply to character array literals.

— end note]

🔗

constexpr chrono::milliseconds                 operator""ms(unsigned long msec);
constexpr chrono::duration<unspecified, milli> operator""ms(long double msec);

Returns: A duration literal representing msec milliseconds.

🔗

constexpr chrono::microseconds                 operator""us(unsigned long usec);
constexpr chrono::duration<unspecified, micro> operator""us(long double usec);

Returns: A duration literal representing usec microseconds.

🔗

constexpr chrono::nanoseconds                 operator""ns(unsigned long nsec);
constexpr chrono::duration<unspecified, nano> operator""ns(long double nsec);

Returns: A duration literal representing nsec nanoseconds.