Defined in header <memory>
template< class ForwardIt, class Size >
ForwardIt destroy_n( ForwardIt first, Size n );
(since C++17)
(until C++20)
template< class ForwardIt, class Size >
constexpr ForwardIt destroy_n( ForwardIt first, Size n );
(since C++20)
template< class ExecutionPolicy, class ForwardIt, class Size >
ForwardIt destroy_n( ExecutionPolicy&& policy, ForwardIt first, Size n );
(2) (since C++17)
1) Destroys the n objects in the range starting at first, as if by
for (; n > 0; (void) ++first, --n)
2) Same as (1), but executed according to policy. This overload does not participate in overload resolution unless

std::is_execution_policy_v<std::decay_t<ExecutionPolicy>> is true.

(until C++20)

std::is_execution_policy_v<std::remove_cvref_t<ExecutionPolicy>> is true.

(since C++20)


first - the beginning of the range of elements to destroy
n - the number of elements to destroy
policy - the execution policy to use. See execution policy for details.
Type requirements
-ForwardIt must meet the requirements of LegacyForwardIterator.
-No increment, assignment, comparison, or indirection through valid instances of ForwardIt may throw exceptions.

Return value

The end of the range of objects that has been destroyed (i.e., std::next(first, n)).


Linear in n.


The overload with a template parameter named ExecutionPolicy reports errors as follows:

  • If execution of a function invoked as part of the algorithm throws an exception and ExecutionPolicy is one of the standard policies, std::terminate is called. For any other ExecutionPolicy, the behavior is implementation-defined.
  • If the algorithm fails to allocate memory, std::bad_alloc is thrown.

Possible implementation

template<class ForwardIt, class Size>
constexpr // since C++20
ForwardIt destroy_n(ForwardIt first, Size n)
    for (; n > 0; (void) ++first, --n)
    return first;


The following example demonstrates how to use destroy_n to destroy a contiguous sequence of elements.

#include <iostream>
#include <memory>
#include <new>
struct Tracer
    int value;
    ~Tracer() { std::cout << value << " destructed\n"; }
int main()
    alignas(Tracer) unsigned char buffer[sizeof(Tracer) * 8];
    for (int i = 0; i < 8; ++i)
        new(buffer + sizeof(Tracer) * i) Tracer{i}; //manually construct objects
    auto ptr = std::launder(reinterpret_cast<Tracer*>(buffer));
    std::destroy_n(ptr, 8);


0 destructed
1 destructed
2 destructed
3 destructed
4 destructed
5 destructed
6 destructed
7 destructed

See also

destroys a range of objects
(function template)
destroys an object at a given address
(function template)
destroys a number of objects in a range

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