Creates aT object initialized with the arguments inargs at given addresslocation.

Equivalent toifconstexpr(std::is_array_v<T>)
    return::new(voidify (*location)) T[1]();
else
    return::new(voidify (*location)) T(std::forward<Args>(args)...);, except thatconstruct_at may be used in evaluation ofconstant expressions(until C++26).

Whenconstruct_at is called in the evaluation of some constant expressionexpr,location must point to either a storage obtained bystd::allocator<T>::allocate or an object whose lifetime began within the evaluation ofexpr.

This overload participates in overload resolution only if all following conditions are satisfied:

• std::is_unbounded_array_v<T> isfalse.
• ::new(std::declval<void*>()) T(std::declval<Args>()...) is well-formed when treated as anunevaluated operand.

Ifstd::is_array_v<T> istrue andsizeof...(Args) is nonzero, the program is ill-formed.

[edit]Parameters

[edit]Return value

location

[edit]Example

#include <bit>#include <memory> class S{int x_;float y_;double z_;public:constexpr S(int x,float y,double z): x_{x}, y_{y}, z_{z}{}[[nodiscard("no side-effects!")]]constexprbool operator==(const S&)constnoexcept=default;}; constevalbool test(){    alignas(S)unsignedchar storage[sizeof(S)]{};    S uninitialized=std::bit_cast<S>(storage);std::destroy_at(&uninitialized);    S* ptr= std::construct_at(std::addressof(uninitialized),42,2.71f,3.14);constbool res{*ptr== S{42,2.71f,3.14}};std::destroy_at(ptr);return res;}static_assert(test()); int main(){}

[edit]Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

[edit]See also

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