Inserts a new element into the container constructed in-place with the givenargs.

The constructor of the new element (i.e.std::pair<const Key, T>) is called with exactly the same arguments as supplied toemplace, forwarded viastd::forward<Args>(args)....

Ifvalue_type is notEmplaceConstructible intomultimap fromargs, the behavior is undefined.

No iterators or references are invalidated.

[edit]Parameters

[edit]Return value

An iterator to the inserted element.

[edit]Exceptions

If an exception is thrown for any reason, this function has no effect (strong exception safety guarantee).

[edit]Complexity

Logarithmic in the size of the container.

[edit]Notes

Careful use ofemplace allows the new element to be constructed while avoiding unnecessary copy or move operations.

[edit]Example

#include <iostream>#include <string>#include <utility>#include <map> int main(){std::multimap<std::string,std::string> m; // uses pair's move constructor    m.emplace(std::make_pair(std::string("a"),std::string("a"))); // uses pair's converting move constructor    m.emplace(std::make_pair("b","abcd")); // uses pair's template constructor    m.emplace("d","ddd"); // emplace with duplicate key    m.emplace("d","DDD"); // uses pair's piecewise constructor    m.emplace(std::piecewise_construct,std::forward_as_tuple("c"),std::forward_as_tuple(10,'c')); for(constauto& p: m)std::cout<< p.first<<" => "<< p.second<<'\n';}

a => ab => abcdc => ccccccccccd => dddd => DDD

[edit]See also

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