95 lines
4.3 KiB
Markdown
95 lines
4.3 KiB
Markdown
[exec.getcomplsigs]
|
||
|
||
# 33 Execution control library [[exec]](./#exec)
|
||
|
||
## 33.9 Senders [[exec.snd]](exec.snd#exec.getcomplsigs)
|
||
|
||
### 33.9.9 execution::get_completion_signatures [exec.getcomplsigs]
|
||
|
||
[ð](#itemdecl:1)
|
||
|
||
`template<class Sndr, class... Env>
|
||
consteval auto get_completion_signatures() -> [valid-completion-signatures](execution.syn#concept:valid-completion-signatures "33.4 Header <execution> synopsis [execution.syn]") auto;
|
||
`
|
||
|
||
[1](#1)
|
||
|
||
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/exec.tex#L2634)
|
||
|
||
Let except be an rvalue subexpression of
|
||
an unspecified class type Except such that[move_constructible](concept.moveconstructible#concept:move_constructible "18.4.13 Concept move_constructible [concept.moveconstructible]")<Except> && [derived_from](concept.derived#concept:derived_from "18.4.3 Concept derived_from [concept.derived]")<Except, exception> is true[.](#1.sentence-1)
|
||
|
||
Let *CHECKED-COMPLSIGS*(e) be e if e is a core constant expression whose
|
||
type satisfies [*valid-completion-signatures*](execution.syn#concept:valid-completion-signatures "33.4 Header <execution> synopsis [execution.syn]");
|
||
otherwise, it is the following expression:(e, throw except, completion_signatures())
|
||
|
||
Let *get-complsigs*<Sndr, Env...>() be expression-equivalent toremove_reference_t<Sndr>::template get_completion_signatures<Sndr, Env...>()[.](#1.sentence-3)
|
||
|
||
Let NewSndr be Sndr if sizeof...(Env) == 0 is true;
|
||
otherwise, decltype(s) where s is the following expression:transform_sender(*get-domain-late*(declval<Sndr>(), declval<Env>()...),
|
||
declval<Sndr>(),
|
||
declval<Env>()...)
|
||
|
||
[2](#2)
|
||
|
||
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/exec.tex#L2660)
|
||
|
||
*Constraints*: sizeof...(Env) <= 1 is true[.](#2.sentence-1)
|
||
|
||
[3](#3)
|
||
|
||
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/exec.tex#L2664)
|
||
|
||
*Effects*: Equivalent to: return e; where e is expression-equivalent to the following:
|
||
|
||
- [(3.1)](#3.1)
|
||
|
||
*CHECKED-COMPLSIGS*(*get-complsigs*<NewSndr, Env...>()) if *get-complsigs*<NewSndr, Env
|
||
...>() is a well-formed expression[.](#3.1.sentence-1)
|
||
|
||
- [(3.2)](#3.2)
|
||
|
||
Otherwise,*CHECKED-COMPLSIGS*(*get-complsigs*<NewSndr>()) if *get-complsigs*<NewSndr>() is a well-formed expression[.](#3.2.sentence-1)
|
||
|
||
- [(3.3)](#3.3)
|
||
|
||
Otherwise,completion_signatures<*SET-VALUE-SIG*(*await-result-type*<NewSndr, *env-promise*<Env>...>), // [[exec.snd.concepts]](exec.snd.concepts "33.9.3 Sender concepts") set_error_t(exception_ptr),
|
||
set_stopped_t()> if [*is-awaitable*](exec.awaitable#concept:is-awaitable "33.9.4 Awaitable helpers [exec.awaitable]")<NewSndr, *env-promise*<Env>...> is true[.](#3.3.sentence-1)
|
||
|
||
- [(3.4)](#3.4)
|
||
|
||
Otherwise,(throw *dependent-sender-error*(), completion_signatures()) if sizeof...(
|
||
Env) == 0 is true,
|
||
where *dependent-sender-error* isdependent_sender_error or
|
||
an unspecified type derived publicly and unambiguously fromdependent_sender_error[.](#3.4.sentence-1)
|
||
|
||
- [(3.5)](#3.5)
|
||
|
||
Otherwise,(throw except, completion_signatures())[.](#3.5.sentence-1)
|
||
|
||
[4](#4)
|
||
|
||
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/exec.tex#L2706)
|
||
|
||
Given a type Env, ifcompletion_signatures_of_t<Sndr> andcompletion_signatures_of_t<Sndr, Env> are both well-formed,
|
||
they shall denote the same type[.](#4.sentence-1)
|
||
|
||
[5](#5)
|
||
|
||
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/exec.tex#L2713)
|
||
|
||
Let rcvr be an rvalue
|
||
whose type Rcvr models [receiver](exec.recv.concepts#concept:receiver "33.7.1 Receiver concepts [exec.recv.concepts]"), and
|
||
let Sndr be the type of a sender
|
||
such that [sender_in](exec.snd.concepts#concept:sender_in "33.9.3 Sender concepts [exec.snd.concepts]")<Sndr, env_of_t<Rcvr>> is true[.](#5.sentence-1)
|
||
|
||
Let Sigs... be the template arguments of
|
||
the completion_signatures specialization
|
||
named by completion_signatures_of_t<Sndr, env_of_t<Rcvr>>[.](#5.sentence-2)
|
||
|
||
Let CSO be a completion function[.](#5.sentence-3)
|
||
|
||
If sender Sndr or its operation state cause
|
||
the expression CSO(rcvr, args...) to be potentially evaluated ([[basic.def.odr]](basic.def.odr "6.3 One-definition rule"))
|
||
then there shall be a signature Sig in Sigs... such that*MATCHING-SIG*(*decayed-typeof*<CSO>(decltype(args)...), Sig) is true ([[exec.general]](exec.general "33.1 General"))[.](#5.sentence-4)
|