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.
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:
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 )
