std::bad_optional_access

 

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std::optional

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optional::optional

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optional::operator->optional::operator*

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swap(std::optional)

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bad_optional_access

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Defined in header <optional>
class bad_optional_access;		(since C++17)

Defines a type of object to be thrown by std::optional::value when accessing an optional object that does not contain a value.

Inheritance diagram

Member functions

(constructor)	constructs a new bad_optional_access object (public member function)
operator=	replaces the bad_optional_access object (public member function)
what	returns the explanatory string (public member function)

std::bad_optional_access::bad_optional_access

bad_optional_access() noexcept;	(1)	(since C++17)
bad_optional_access( const bad_optional_access& other ) noexcept;	(2)	(since C++17)

Constructs a new bad_optional_access object with an implementation-defined null-terminated byte string which is accessible through what().

1) Default constructor.

2) Copy constructor. If *this and other both have dynamic type std::bad_optional_access then std::strcmp(what(), other.what()) == 0.

Parameters

other

-

another exception object to copy

std::bad_optional_access::operator=

bad_optional_access& operator=( const bad_optional_access& other ) noexcept;		(since C++17)

Assigns the contents with those of other. If *this and other both have dynamic type std::bad_optional_access then std::strcmp(what(), other.what()) == 0 after assignment.

Parameters

other

-

another exception object to assign with

Return value

*this

std::bad_optional_access::what

virtual const char* what() const noexcept;		(since C++17)

Returns the explanatory string.

Parameters

(none)

Return value

Pointer to a null-terminated string with explanatory information. The string is suitable for conversion and display as a std::wstring. The pointer is guaranteed to be valid at least until the exception object from which it is obtained is destroyed, or until a non-const member function (e.g. copy assignment operator) on the exception object is called.

Notes

Implementations are allowed but not required to override what().

Inherited from std::exception

Member functions

(destructor) [virtual]	destroys the exception object (virtual public member function of std::exception)
what [virtual]	returns an explanatory string (virtual public member function of std::exception)