asio/doc/requirements/TimeTraits.qbk
2019-02-17 19:59:39 -10:00

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[/
/ Copyright (c) 2003-2019 Christopher M. Kohlhoff (chris at kohlhoff dot com)
/
/ Distributed under the Boost Software License, Version 1.0. (See accompanying
/ file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
/]
[section:TimeTraits Time traits requirements]
In the table below, `X` denotes a time traits class for time type `Time`, `t`,
`t1`, and `t2` denote values of type `Time`, and `d` denotes a value of type
`X::duration_type`.
[table TimeTraits requirements
[[expression] [return type] [assertion/note\npre/post-condition]]
[
[`X::time_type`]
[`Time`]
[
Represents an absolute time. Must support default construction, and meet
the requirements for `CopyConstructible` and `Assignable`.
]
]
[
[`X::duration_type`]
[]
[
Represents the difference between two absolute times. Must support
default construction, and meet the requirements for `CopyConstructible`
and `Assignable`. A duration can be positive, negative, or zero.
]
]
[
[`X::now();`]
[`time_type`]
[
Returns the current time.
]
]
[
[`X::add(t, d);`]
[`time_type`]
[
Returns a new absolute time resulting from adding the duration `d` to the
absolute time `t`.
]
]
[
[`X::subtract(t1, t2);`]
[`duration_type`]
[
Returns the duration resulting from subtracting `t2` from `t1`.
]
]
[
[`X::less_than(t1, t2);`]
[`bool`]
[
Returns whether `t1` is to be treated as less than `t2`.
]
]
[
[`X::to_posix_duration(d);`]
[`date_time::time_duration_type`]
[
Returns the `date_time::time_duration_type` value that most closely
represents the duration `d`.
]
]
]
[endsect]