eagine::ok< Outcome > Class Template Reference

Value typically wrapping function call result and success indicator. More...

#include <eagine/extract.hpp>

Public Member Functions
constexpr	ok (Outcome &&outcome) noexcept(noexcept(std::declval< Outcome && >()))
	Construction from a function call outcome object.
constexpr	operator bool () noexcept(noexcept(bool(std::declval< Outcome & >())))
	Indicates if the stored outcome contains valid result value.
constexpr	operator bool () const noexcept(noexcept(bool(std::declval< const Outcome & >())))
	Indicates if the stored outcome contains valid result value.
constexpr auto	get () noexcept(noexcept(extract(_outcome))) -> decltype(extract(_outcome))
	Extracts the stored outcome value. More...
constexpr auto	get () const noexcept(noexcept(extract(_outcome))) -> decltype(extract(_outcome))
	Extracts the stored outcome value. More...
constexpr	operator decltype (extract(std::declval< Outcome & >()))() noexcept(noexcept(extract(_outcome)))
	Implicit conversion to the stored outcome value. More...
constexpr	operator decltype (extract(std::declval< const Outcome & >()))() const noexcept(noexcept(extract(_outcome)))
	Implicit conversion to the stored outcome value. More...

Related Functions
(Note that these are not member functions.)
template<typename Outcome >
auto	extract (const ok< Outcome > &x) noexcept -> const auto &
	Overload of extract for instantiations of the ok template.
template<typename Outcome >
auto	begin (const ok< Outcome > &x, decltype(std::declval< const ok< Outcome > & >().get().begin()) *=nullptr)
	Overload of begin for instantiations of the ok template.
template<typename Outcome >
auto	end (const ok< Outcome > &x, decltype(std::declval< const ok< Outcome > & >().get().end()) *=nullptr)
	Overload of begin for instantiations of the ok template.

Detailed Description

template<typename Outcome>
class eagine::ok< Outcome >

Value typically wrapping function call result and success indicator.

Template Parameters

Outcome

the actual function call result type.

See also

ok_traits

valid_if

Instances of this class are used to store the result of a function call and store the actual result together with some ingication whether the call was actually successful. This means that the stored result value is only optionally valid as indicated by the conversion-to-boolean operator.

The ok class can, depending on specializations of ok_traits, provide additional information about why the associated function call failed, for example an error code or error message string, etc.

This class is typically used to store and retrieve C-API function call results where the success is indicated by errno or some such global variable.

Examples

eglplus/001_basic_info.cpp, eglplus/003_list_extensions.cpp, eglplus/005_list_configs.cpp, eglplus/006_multisample_configs.cpp, eglplus/007_depth_stencil_configs.cpp, eglplus/008_list_extensions.cpp, oalplus/005_hello_world.cpp, and oglplus/001_glfw3_glew_info.cpp.

Member Function Documentation

get() [1/2]

template<typename Outcome >

constexpr auto eagine::ok< Outcome >::get ( ) const -> decltype(extract(_outcome))

inlineconstexprnoexcept

Extracts the stored outcome value.

Precondition

bool(*this)

get() [2/2]

template<typename Outcome >

constexpr auto eagine::ok< Outcome >::get ( ) -> decltype(extract(_outcome))

inlineconstexprnoexcept

Extracts the stored outcome value.

Precondition

bool(*this)

operator decltype() [1/2]

template<typename Outcome >

constexpr eagine::ok< Outcome >::operator decltype ( extract(std::declval< const Outcome & >())  ) const

inlineconstexprnoexcept

Implicit conversion to the stored outcome value.

Precondition

bool(*this)

operator decltype() [2/2]

template<typename Outcome >

constexpr eagine::ok< Outcome >::operator decltype ( extract(std::declval< Outcome & >())  )

inlineconstexprnoexcept

Implicit conversion to the stored outcome value.

Precondition

bool(*this)

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

• eagine/extract.hpp