std::experimental::optional<T>::emplace

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Library fundamentals

experimental::optional
experimental::any
experimental::basic_string_view
experimental::sample
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experimental::weak_ptr
experimental::apply
experimental::invocation_typeexperimental::raw_invocation_type
experimental::search
experimental::default_searcherexperimental::make_default_searcher
experimental::boyer_moore_searcherexperimental::make_boyer_moore_searcher
experimental::boyer_moore_horspool_searcherexperimental::make_boyer_moore_horspool_searcher
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std::experimental::optional

Member functions
optional::optional
optional::~optional
optional::operator=
Observers
optional::operator->optional::operator*
optional::operator bool
optional::value
optional::value_or
Modifiers
optional::emplace
optional::swap
Non-member functions
operator==operator!=operator<operator<=operator>operator>=
make_optional
swap
Helper classes
hash
nullopt_t
in_place_t
bad_optional_access
Helper objects
nullopt
in_place

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template<class...Args> void emplace( Args&&...args);		(library fundamentals TS)
template<class U,class...Args> void emplace(std::initializer_list<U> ilist, Args&&...args);		(library fundamentals TS)

Constructs the contained value in-place. If*this already contains a value before the call, the contained value is destroyed by calling its destructor.

1) Initializes the contained value bydirect-initializing (but not direct-list-initializing) withstd::forward<Args>(args)... as parameters.

2) Initializes the contained value by calling its constructor withilist,std::forward<Args>(args)... as parameters. This overload participates in overload resolution only ifstd::is_constructible<T,std::initializer_list<U>&, Args&&...>::value istrue.

[edit]Parameters

args...	-	the arguments to pass to the constructor
ilist	-	the initializer list to pass to the constructor
Type requirements
- `T` must be constructible from`Args...`
- `T` must be constructible fromstd::initializer_list and`Args...`

[edit]Return value

(none)

[edit]Exceptions

Any exception thrown by the selected constructor ofT. If an exception is thrown,*this does not contain a value after this call (the previously contained value, if any, had been destroyed).