<chrono>

Time library

chrono is the name of a header, but also of a sub-namespace: All the elements in this header (except for the common_type specializations) are not defined directly under the std namespace (like most of the standard library) but under the std::chrono namespace.

The elements in this header deal with time. This is done mainly by means of three concepts:

Durations: They measure time spans, like: one minute, two hours, or ten milliseconds.
In this library, they are represented with objects of the duration class template, that couples a count representation and a period precision (e.g., ten milliseconds has ten as count representation and milliseconds as period precision).
Time points: A reference to a specific point in time, like one's birthday, today's dawn, or when the next train passes.
In this library, objects of the time_point class template express this by using a duration relative to an epoch (which is a fixed point in time common to all time_point objects using the same clock).
Clocks: A framework that relates a time point to real physical time.
The library provides at least three clocks that provide means to express the current time as a time_point: system_clock, steady_clock and high_resolution_clock.

For typical examples, see steady_clock or system_clock.

Classes

`duration` and `time_point`:

duration: Duration (class template)

time_point: Time point (class template)

clocks:

system_clock: System clock (class)

steady_clock: Steady clock (class)

high_resolution_clock: High resolution clock (class)

traits:

treat_as_floating_point: Treat as floating point (class template)

duration_values: Duration values (class template)

common_type (duration): Specialization of common_type for duration (class template)

Functions

duration_cast: Duration cast (function template)

time_point_cast: Time_point cast (function template)

Class instantiation typedefs

The following convenience typedefs of instantiations of duration are also defined in this namespace:

hours: Duration in hours (class)

minutes: Duration in minutes (class)

seconds: Duration in seconds (class)

milliseconds: Duration in milliseconds (class)

microseconds: Duration in microseconds (class)

nanoseconds: Duration in nanoseconds (class)

classes

functions

class typedefs