[header][other] chrono (C++11)

*[header][other] chrono (C++11)

<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 )

내용 출처 : http://www.cplusplus.com/reference/chrono/