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std::experimental::optional::emplace(3) | C++ Standard Libary | std::experimental::optional::emplace(3) |
NAME¶
std::experimental::optional::emplace - std::experimental::optional::emplace
Synopsis¶
template< class... Args > (library fundamentals TS)
void emplace( Args&&... args );
template< class U, class... Args >
void emplace( std::initializer_list<U> ilist, Args&&...
(library fundamentals TS)
args );
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 by direct-initializing (but not
direct-list-initializing) with std::forward<Args>(args)... as
parameters.
2) Initializes the contained value by calling its constructor with ilist,
std::forward<Args>(args)... as parameters. This overload participates
in overload
resolution only if std::is_constructible<T,
std::initializer_list<U>&,
Args&&...>::value is true.
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 from std::initializer_list and Args...
Return value¶
(none)
Exceptions¶
Any exception thrown by the selected constructor of T. If an
exception is thrown,
*this does not contain a value after this call (the previously contained
value, if
any, had been destroyed).
See also¶
operator= assigns contents
(public member function)
Category:¶
* Noindexed pages
2024.06.10 | http://cppreference.com |