NAME

std::bad_optional_access - std::bad_optional_access

Synopsis

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.

std-bad optional access-inheritance-lwg2806.svg

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 ) (since C++17)
noexcept;

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