[exec.domain.default]

# 33 Execution control library [[exec]](./#exec)

## 33.9 Senders [[exec.snd]](exec.snd#exec.domain.default)

### 33.9.5 execution​::​default_domain [exec.domain.default]

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/exec.tex#L2425)

namespace std::execution {struct [default_domain](#lib:default_domain "33.9.5 execution​::​default_­domain [exec.domain.default]") {template<[sender](exec.snd.concepts#concept:sender "33.9.3 Sender concepts [exec.snd.concepts]") Sndr, [*queryable*](exec.queryable.concept#concept:queryable "33.2.2 queryable concept [exec.queryable.concept]")... Env>requires (sizeof...(Env) <= 1)static constexpr [sender](exec.snd.concepts#concept:sender "33.9.3 Sender concepts [exec.snd.concepts]") decltype(auto) transform_sender(Sndr&& sndr, const Env&... env)noexcept(*see below*); template<[sender](exec.snd.concepts#concept:sender "33.9.3 Sender concepts [exec.snd.concepts]") Sndr, [*queryable*](exec.queryable.concept#concept:queryable "33.2.2 queryable concept [exec.queryable.concept]") Env>static constexpr [*queryable*](exec.queryable.concept#concept:queryable "33.2.2 queryable concept [exec.queryable.concept]") decltype(auto) transform_env(Sndr&& sndr, Env&& env) noexcept; template<class Tag, [sender](exec.snd.concepts#concept:sender "33.9.3 Sender concepts [exec.snd.concepts]") Sndr, class... Args>static constexpr decltype(auto) apply_sender(Tag, Sndr&& sndr, Args&&... args)noexcept(*see below*); };}

[ð](#lib:transform_sender,default_domain)

`template<[sender](exec.snd.concepts#concept:sender "33.9.3 Sender concepts [exec.snd.concepts]") Sndr, [queryable](exec.queryable.concept#concept:queryable "33.2.2 queryable concept [exec.queryable.concept]")... Env>
  requires (sizeof...(Env) <= 1)
constexpr [sender](exec.snd.concepts#concept:sender "33.9.3 Sender concepts [exec.snd.concepts]") decltype(auto) transform_sender(Sndr&& sndr, const Env&... env)
  noexcept(see below);
`

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/exec.tex#L2453)

Let e be the expressiontag_of_t<Sndr>().transform_sender(std::forward<Sndr>(sndr), env...) if that expression is well-formed;
otherwise, std​::​forward<Sndr>(sndr)[.](#2.sentence-1)

[3](#3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/exec.tex#L2461)

*Returns*: e[.](#3.sentence-1)

[4](#4)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/exec.tex#L2465)

*Remarks*: The exception specification is equivalent to noexcept(e)[.](#4.sentence-1)

[ð](#lib:transform_env,default_domain)

`template<[sender](exec.snd.concepts#concept:sender "33.9.3 Sender concepts [exec.snd.concepts]") Sndr, [queryable](exec.queryable.concept#concept:queryable "33.2.2 queryable concept [exec.queryable.concept]") Env>
  constexpr [queryable](exec.queryable.concept#concept:queryable "33.2.2 queryable concept [exec.queryable.concept]") decltype(auto) transform_env(Sndr&& sndr, Env&& env) noexcept;
`

[5](#5)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/exec.tex#L2477)

Let e be the expressiontag_of_t<Sndr>().transform_env(std::forward<Sndr>(sndr), std::forward<Env>(env)) if that expression is well-formed;
otherwise, *FWD-ENV*(std​::​forward<Env>(env))[.](#5.sentence-1)

[6](#6)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/exec.tex#L2485)

*Mandates*: noexcept(e) is true[.](#6.sentence-1)

[7](#7)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/exec.tex#L2489)

*Returns*: e[.](#7.sentence-1)

[ð](#lib:apply_sender,default_domain)

`template<class Tag, [sender](exec.snd.concepts#concept:sender "33.9.3 Sender concepts [exec.snd.concepts]") Sndr, class... Args>
constexpr decltype(auto) apply_sender(Tag, Sndr&& sndr, Args&&... args)
  noexcept(see below);
`

[8](#8)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/exec.tex#L2502)

Let e be the expression Tag().apply_sender(std::forward<Sndr>(sndr), std::forward<Args>(args)...)

[9](#9)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/exec.tex#L2508)

*Constraints*: e is a well-formed expression[.](#9.sentence-1)

[10](#10)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/exec.tex#L2512)

*Returns*: e[.](#10.sentence-1)

[11](#11)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/exec.tex#L2516)

*Remarks*: The exception specification is equivalent to noexcept(e)[.](#11.sentence-1)
