pw::async2::Poll< T > Class Template Reference

Overview

template<typename T>
class pw::async2::Poll< T >

A value that may or may not be ready yet.

Poll<T> most commonly appears as the return type of an function that checks the current status of an asynchronous operation. If the operation has completed, it returns with Ready(value). Otherwise, it returns Pending to indicate that the operations has not yet completed, and the caller should try again in the future.

Poll<T> is just data and does not change on its own. To check the current status of an operation, the caller must invoke the Poll<T> returning function again and examine the newly returned Poll<T>.

Public Types
using	value_type = T

Public Member Functions
	Poll ()=delete
	Basic constructors.
constexpr	Poll (const Poll &)=default
constexpr Poll &	operator= (const Poll &)=default
constexpr	Poll (Poll &&)=default
constexpr Poll &	operator= (Poll &&)=default
template<typename U , internal_poll::EnableIfImplicitlyConvertible< value_type, const U & > = 0>
constexpr	Poll (const Poll< U > &other)
template<typename U , internal_poll::EnableIfExplicitlyConvertible< value_type, const U & > = 0>
constexpr	Poll (const Poll< U > &other)
template<typename U , internal_poll::EnableIfImplicitlyConvertible< value_type, U && > = 0>
constexpr	Poll (Poll< U > &&other)
template<typename U , internal_poll::EnableIfExplicitlyConvertible< value_type, U && > = 0>
constexpr	Poll (Poll< U > &&other)
template<typename U = value_type, internal_poll::EnableIfImplicitlyInitializable< value_type, U > = 0>
constexpr	Poll (U &&u)
template<typename U = value_type, internal_poll::EnableIfExplicitlyInitializable< value_type, U > = 0>
constexpr	Poll (U &&u)
template<typename... Args>
constexpr	Poll (std::in_place_t, Args &&... args)
constexpr	Poll (value_type &&value)
constexpr Poll &	operator= (value_type &&value)
constexpr	Poll (PendingType) noexcept
constexpr Poll &	operator= (PendingType) noexcept
constexpr bool	IsReady () const noexcept
	Returns whether or not this value is Ready.
constexpr bool	IsPending () const noexcept
	Returns whether or not this value is Pending.
constexpr Poll	Readiness () const noexcept
constexpr value_type &	value () &noexcept
constexpr const value_type &	value () const &noexcept
constexpr value_type &&	value () &&noexcept
constexpr const value_type &&	value () const &&noexcept
constexpr const value_type *	operator-> () const noexcept
constexpr value_type *	operator-> () noexcept
constexpr const value_type &	operator* () const &noexcept
constexpr value_type &	operator* () &noexcept
constexpr const value_type &&	operator* () const &&noexcept
constexpr value_type &&	operator* () &&noexcept
constexpr void	IgnorePoll () const

Constructor & Destructor Documentation

Poll()

template<typename T >

template<typename U , internal_poll::EnableIfImplicitlyConvertible< value_type, const U & > = 0>

constexpr pw::async2::Poll< T >::Poll ( const Poll< U > &  other )

inlineconstexpr

Constructs a new Poll<T> from a Poll<U> where T is constructible from U.

To avoid ambiguity, this constructor is disabled if T is also constructible from Poll<U>.

This constructor is explicit if and only if the corresponding construction of T from U is explicit.

Member Function Documentation

IgnorePoll()

template<typename T >

constexpr void pw::async2::Poll< T >::IgnorePoll ( ) const

inlineconstexpr

Ignores the Poll value.

This method does nothing except prevent no_discard or unused variable warnings from firing.

operator*()

template<typename T >

constexpr const value_type & pw::async2::Poll< T >::operator* ( ) const &

inlineconstexprnoexcept

Returns the inner value.

This must only be called if IsReady() returned true.

operator->()

template<typename T >

constexpr const value_type * pw::async2::Poll< T >::operator-> ( ) const

inlineconstexprnoexcept

Accesses the inner value.

This must only be called if IsReady() returned true.

Readiness()

template<typename T >

constexpr Poll pw::async2::Poll< T >::Readiness ( ) const

inlineconstexprnoexcept

Returns a Poll<> without the inner value whose readiness matches that of this.

value()

template<typename T >

constexpr value_type & pw::async2::Poll< T >::value ( ) &

inlineconstexprnoexcept

Returns the inner value.

This must only be called if IsReady() returned true.

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The documentation for this class was generated from the following file:

• pw_async2/public/pw_async2/poll.h