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

template< class... Args >
constexpr reference unchecked_emplace_back( Args&&... args );

(since C++26)

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

args	-	arguments to forward to the constructor of the element
Type requirements
-`T` must be EmplaceConstructible into `inplace_vector` from `std::forward<Args>(args)...`.

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
}

Output:

fauna = [("🐈", "🐕"), ("🐈", "🐕")]

emplace_back	constructs an element in-place at the end (public member function)
append_range	adds a range of elements to the end (public member function)
push_back	adds an element to the end (public member function)
try_push_back	tries to add an element to the end (public member function)
try_emplace_back	tries to construct an element in-place at the end (public member function)
try_append_range	tries to add a range of elements to the end (public member function)
unchecked_push_back	unconditionally adds an element to the end (public member function)
pop_back	removes the last element (public member function)
back_inserter	creates a `std::back_insert_iterator` of type inferred from the argument (function template)

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