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std::any::any

constexpr any();
 (1) (since C++17) 
any( const any& other );
 (2) (since C++17) 
any( any&& other );
 (3) (since C++17) 
template< class ValueType >
any( ValueType&& value );
 (4) (since C++17) 
template< class T, class... Args >
explicit any( std::in_place_type_t<T>, Args&&... args );
 (5) (since C++17) 
template< class T, class U, class... Args >
explicit any( std::in_place_type_t<T>, std::initializer_list<U> il,
              Args&&... args );
 (6) (since C++17)

Constructs a new any object.

1) Constructs an empty object.
2-3) Copies (2) or moves (3) content of other into a new instance, so that any content is equivalent in both type and value to those of other prior to the constructor call, or empty if other is empty.
4) Constructs an object with initial content an object of type std::decay_t<ValueType>, direct-initialized from std::forward<ValueType>(value). If std::is_copy_constructible<std::decay_t<ValueType>>::value is false, the program is ill-formed. This overload only participates in overload resolution if std::decay_t<ValueType> is not the same type as any.
5) Constructs an object with initial content an object of type T, direct-non-list-initialized from std::forward<Args>(args).... If std::is_constructible_v<T, Args...> is false, the behavior is undefined.
6) Constructs an object with initial content an object of type T, direct-non-list-initialized from il, std::forward<Args>(args).... This overload only participates in overload resolution if std::is_constructible_v<T, std::initializer_list<U>&, Args...> is true.

Template parameters

ValueType - contained value type
Type requirements
- std::decay_t<ValueType> must meet the requirements of CopyConstructible.

Parameters

other - another any object to copy or move from
value - value to initialize the contained value with
il, args - arguments to be passed to the constructor of the contained object

Exceptions

1,3)
noexcept specification:
noexcept
2,4,5,6) Throws any exception thrown by the constructor of the contained type.

Notes

Because the default constructor is constexpr, static std::anys are initialized as part of static non-local initialization, before any dynamic non-local initialization begins. This makes it safe to use an object of type std::any in a constructor of any static object.

See also

 assigns an any object
(public member function)

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