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    {{cpp/utility/optional/title|emplace}}
    {{cpp//optional/title|emplace}}
    {{cpp/utility/optional/navbar}}
    {{cpp//optional/navbar}}
    {{dcl begin}}
    {{dcl begin}}
    {{dcl | notes={{mark since c++14}} | 1=
    {{dcl | =| 1=
    template< class... Args >  
    template< class... Args >  
    void emplace( Args&&... args );
    void emplace( Args&&... args );
    }}
    }}
    {{dcl | notes={{mark since c++14}} | 1=
    {{dcl | =| 1=
    template< class U, class... Args >  
    template< class U, class... Args >  
    void emplace( std::initializer_list<U> ilist, Args&&... args );
    void emplace( std::initializer_list<U> ilist, Args&&... args );
    Line 12: Line 12:
    {{dcl end}}
    {{dcl end}}


    Constructs the contained value in-place. If {{c|*this}} is in initialized state before the call, the contained value is destroyed by calling its destructor.
    Constructs the contained value in-place. If {{c|*this}} before the call, the contained value is destroyed by calling its destructor.


    @1@ Initializes the contained value by calling its constructor with {{tt|args...}} as parameters.
    @1@ Initializes the contained value by with {{|args...}} as parameters.


    @2@ Inilializes the contained value by calling its constructor with {{tt|ilist}} and {{tt|args...}} as parameters.
    @2@ the contained value by calling its constructor with {{|ilist}} {{|...}}.


    ===Parameters===
    ===Parameters===
    Line 31: Line 31:


    ===Exceptions===
    ===Exceptions===
    Any exception thrown by the selected constructor of {{tt|T}}. If an exception is thrown, {{c|*this}} is in uninitialized state after the call.
    Any exception thrown by the selected constructor of {{tt|T}}. If an exception is thrown, {{c|*this}} after the .


    ===See also===
    ===See also===
    {{dsc begin}}
    {{dsc begin}}
    {{dsc inc | cpp/utility/optional/dcl list operator{{=}}}}
    {{dsc inc | cpp//optional/operator{{=}}}}
    {{dsc end}}
    {{dsc end}}

    Latest revision as of 06:22, 16 May 2015

     
    C++
     
    Experimental
    Technical Specification
    Filesystem library (filesystem TS)
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    Library fundamentals
     
    std::experimental::optional
     
    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 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

    		 assigns contents
    (public member function) [edit]