From Jason Turner

[time.duration]

C++20 → C++23 3.2 KB 29 lines
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Archived: C++20 | C++23
Markdown: C++20 | C++23
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  1. tmp/tmpdbfj7qm2/{from.md → to.md} +11 -11
tmp/tmpdbfj7qm2/{from.md → to.md} RENAMED
@@ -1,7 +1,9 @@
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  ## Class template `duration` <a id="time.duration">[[time.duration]]</a>
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  A `duration` type measures time between two points in time
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  (`time_point`s). A `duration` has a representation which holds a count
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  of ticks and a tick period. The tick period is the amount of time which
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  occurs from one tick to the next, in units of seconds. It is expressed
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  as a rational constant using the template `ratio`.
@@ -65,12 +67,11 @@ ill-formed. If `Period::num` is not positive, the program is ill-formed.
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  Members of `duration` do not throw exceptions other than those thrown by
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  the indicated operations on their representations.
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  The defaulted copy constructor of duration shall be a constexpr function
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  if and only if the required initialization of the member `rep_` for copy
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- and move, respectively, would satisfy the requirements for a constexpr
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- function.
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  [*Example 1*:
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  ``` cpp
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  duration<long, ratio<60>> d0; // holds a count of minutes using a long
@@ -100,11 +101,11 @@ duration<int, milli> d(3); // OK
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  duration<int, milli> d(3.5); // error
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  ```
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  — *end example*]
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- *Ensures:* `count() == static_cast<rep>(r)`.
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  ``` cpp
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  template<class Rep2, class Period2>
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  constexpr duration(const duration<Rep2, Period2>& d);
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  ```
@@ -597,11 +598,11 @@ where *`units-suffix`* depends on the type `Period::type` as follows:
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  `"d"`.
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  - Otherwise, if `Period::type::den == 1`, *`units-suffix`* is
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  `"[`*`num`*`]s"`.
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  - Otherwise, *`units-suffix`* is `"[`*`num`*`/`*`den`*`]s"`.
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- In the list above, the use of *`num`* and *`den`* refer to the static
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  data members of `Period::type`, which are converted to arrays of `charT`
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  using a decimal conversion with no leading zeroes.
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  *Returns:* `os`.
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@@ -614,15 +615,14 @@ template<class charT, class traits, class Rep, class Period, class Alloc = alloc
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  minutes* offset = nullptr);
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  ```
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  *Effects:* Attempts to parse the input stream `is` into the duration `d`
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  using the format flags given in the NTCTS `fmt` as specified in
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- [[time.parse]]. If the parse parses everything specified by the parsing
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- format flags without error, and yet none of the flags impacts a
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- duration, `d` will be assigned a zero value. If `%Z` is used and
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- successfully parsed, that value will be assigned to `*abbrev` if
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- `abbrev` is non-null. If `%z` (or a modified variant) is used and
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- successfully parsed, that value will be assigned to `*offset` if
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- `offset` is non-null.
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  *Returns:* `is`.
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  ## Class template `duration` <a id="time.duration">[[time.duration]]</a>
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+ ### General <a id="time.duration.general">[[time.duration.general]]</a>
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+
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  A `duration` type measures time between two points in time
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  (`time_point`s). A `duration` has a representation which holds a count
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  of ticks and a tick period. The tick period is the amount of time which
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  occurs from one tick to the next, in units of seconds. It is expressed
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  as a rational constant using the template `ratio`.
 
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  Members of `duration` do not throw exceptions other than those thrown by
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  the indicated operations on their representations.
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  The defaulted copy constructor of duration shall be a constexpr function
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  if and only if the required initialization of the member `rep_` for copy
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+ and move, respectively, would be constexpr-suitable [[dcl.constexpr]].
 
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  [*Example 1*:
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  ``` cpp
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  duration<long, ratio<60>> d0; // holds a count of minutes using a long
 
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  duration<int, milli> d(3.5); // error
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  ```
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  — *end example*]
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+ *Effects:* Initializes `rep_` with `r`.
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  ``` cpp
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  template<class Rep2, class Period2>
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  constexpr duration(const duration<Rep2, Period2>& d);
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  ```
 
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  `"d"`.
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  - Otherwise, if `Period::type::den == 1`, *`units-suffix`* is
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  `"[`*`num`*`]s"`.
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  - Otherwise, *`units-suffix`* is `"[`*`num`*`/`*`den`*`]s"`.
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+ In the list above, the use of *`num`* and *`den`* refers to the static
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  data members of `Period::type`, which are converted to arrays of `charT`
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  using a decimal conversion with no leading zeroes.
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  *Returns:* `os`.
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  minutes* offset = nullptr);
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  ```
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  *Effects:* Attempts to parse the input stream `is` into the duration `d`
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  using the format flags given in the NTCTS `fmt` as specified in
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+ [[time.parse]]. If the parse fails to decode a valid duration,
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+ `is.setstate(ios_base::failbit)` is called and `d` is not modified. If
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+ `%Z` is used and successfully parsed, that value will be assigned to
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+ `*abbrev` if `abbrev` is non-null. If `%z` (or a modified variant) is
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+ used and successfully parsed, that value will be assigned to `*offset`
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+ if `offset` is non-null.
 
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  *Returns:* `is`.
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