dpp::detail::task::promise_t< R > Struct Template Reference

A task's promise_t type, with special logic for handling nested tasks. More...

#include <task.h>

Inheritance diagram for dpp::detail::task::promise_t< R >:

Collaboration diagram for dpp::detail::task::promise_t< R >:

Public Member Functions
	~promise_t ()
	Destructor. Destroys the value if it was constructed. More...
void	return_value (R &&expr) noexcept(std::is_nothrow_move_constructible_v< R >)
	Function called by the standard library when the coroutine co_returns a value. More...
void	return_value (const R &expr) noexcept(std::is_nothrow_copy_constructible_v< R >)
	Function called by the standard library when the coroutine co_returns a value. More...
template<typename T > requires (!std::is_same_v<R, std::remove_cvref_t<T>> && std::convertible_to<T, R>)
void	return_value (T &&expr) noexcept(std::is_nothrow_convertible_v< T, R >)
	Function called by the standard library when the coroutine co_returns a value. More...
dpp::task< R >	get_return_object () noexcept
	Function called by the standard library when the coroutine is created. More...
final_awaiter< R >	final_suspend () const noexcept
	Function called by the standard library when the coroutine reaches its last suspension point. More...
std_coroutine::suspend_never	initial_suspend () const noexcept
	Function called by the standard library when the coroutine is created. More...
void	unhandled_exception ()
	Function called by the standard library when an exception is thrown and not caught in the coroutine. More...
template<typename T >
auto	await_transform (T &&expr) const noexcept(noexcept(co_await_resolve(std::forward< T >(expr))))
	Function called whenever co_await is used inside of the task. More...

Public Attributes
std::array< std::byte, sizeof(R)>	result_storage
	Stored return value of the coroutine. More...
std::atomic< state_t >	state = state_t::started
	State of the task, used to keep track of lifetime and status. More...
std::atomic< bool >	cancelled = false
	Whether the task is cancelled or not. More...
detail::std_coroutine::coroutine_handle	parent = nullptr
	Parent coroutine to return to for nested coroutines. More...

Detailed Description

template<typename R>
struct dpp::detail::task::promise_t< R >

A task's promise_t type, with special logic for handling nested tasks.

Implementation of task::promise_t for non-void return type.

Template Parameters

R	Return type of the task

Constructor & Destructor Documentation

~promise_t()

template<typename R >

dpp::detail::task::promise_t< R >::~promise_t ( )

inline

Destructor. Destroys the value if it was constructed.

Member Function Documentation

await_transform()

template<typename T >

auto dpp::detail::task::promise_base::await_transform ( T &&  expr ) const

inlinenoexceptinherited

Function called whenever co_await is used inside of the task.

Exceptions

dpp::task_cancelled_exception

On resumption if the task was cancelled

Returns

proxy_awaiter Returns a proxy awaiter that will check for cancellation on resumption

final_suspend()

template<typename R >

final_awaiter< R > dpp::detail::task::promise_t< R >::final_suspend ( ) const

inlinenoexcept

Function called by the standard library when the coroutine reaches its last suspension point.

Returns

final_awaiter Special object containing the chain resolution and clean-up logic.

get_return_object()

template<typename R >

dpp::task< R > dpp::detail::task::promise_t< R >::get_return_object ( )

inlinenoexcept

Function called by the standard library when the coroutine is created.

Returns

dpp::task The coroutine object

initial_suspend()

std_coroutine::suspend_never dpp::detail::task::promise_base::initial_suspend ( ) const

inlinenoexceptinherited

Function called by the standard library when the coroutine is created.

Returns

std::suspend_never Don't suspend, the coroutine starts immediately.

return_value() [1/3]

template<typename R >

void dpp::detail::task::promise_t< R >::return_value ( const R &  expr )

inlinenoexcept

Function called by the standard library when the coroutine co_returns a value.

Stores the value internally to hand to the caller when it resumes.

Parameters

expr	The value given to co_return

return_value() [2/3]

template<typename R >

void dpp::detail::task::promise_t< R >::return_value ( R &&  expr )

inlinenoexcept

Function called by the standard library when the coroutine co_returns a value.

Stores the value internally to hand to the caller when it resumes.

Parameters

expr	The value given to co_return

return_value() [3/3]

template<typename R >

template<typename T >
requires (!std::is_same_v<R, std::remove_cvref_t<T>> && std::convertible_to<T, R>)

void dpp::detail::task::promise_t< R >::return_value ( T &&  expr )

inlinenoexcept

Function called by the standard library when the coroutine co_returns a value.

Stores the value internally to hand to the caller when it resumes.

Parameters

expr	The value given to co_return

unhandled_exception()

void dpp::detail::task::promise_base::unhandled_exception ( )

inlineinherited

Function called by the standard library when an exception is thrown and not caught in the coroutine.

Stores the exception pointer to rethrow on co_await. If the task object is destroyed and was not cancelled, throw instead

Member Data Documentation

cancelled

std::atomic<bool> dpp::detail::task::promise_base::cancelled = false

inherited

Whether the task is cancelled or not.

parent

detail::std_coroutine::coroutine_handle dpp::detail::task::promise_base::parent = nullptr

inherited

Parent coroutine to return to for nested coroutines.

result_storage

template<typename R >

std::array<std::byte, sizeof(R)> dpp::detail::task::promise_t< R >::result_storage

Stored return value of the coroutine.

state

std::atomic<state_t> dpp::detail::task::promise_base::state = state_t::started

inherited

State of the task, used to keep track of lifetime and status.