std::inplace_vector<T,N>:: unchecked_emplace_back

Appends a new element to the end of the container. Typically, the element is constructed using placement- new to construct the element in-place at the location provided by the container. The arguments args... are forwarded to the constructor as std:: forward < Args > ( args ) ... . Equivalent to return * try_emplace_back ( std:: forward < Args > ( args ) ... ) ; .

Before the call to this function size ( ) < capacity ( ) must be true . Otherwise, the behavior is undefined.

No iterators or references are invalidated, except end() , which is invalidated if the insertion occurs.

Parameters

Return value

back() , i.e. a reference to the inserted element.

Complexity

Constant.

Exceptions

Any exception thrown by initialization of inserted element. If an exception is thrown for any reason, this function has no effect ( strong exception safety guarantee ).

Notes

Example

#include <inplace_vector>
#include <new>
#include <print>
#include <string>
#include <utility>
 
int main()
{
    std::inplace_vector<std::pair<std::string, std::string>, 2> fauna;
    std::string dog{"\N{DOG}"};
 
    fauna.unchecked_emplace_back("\N{CAT}", dog);
    fauna.unchecked_emplace_back("\N{CAT}", std::move(dog));
    std::println("fauna = {}", fauna);
 
    // fauna.unchecked_emplace_back("BUG", "BUG"); // undefined behavior: no space
}

fauna = [("🐈", "🐕"), ("🐈", "🐕")]

See also