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std::destroy(3) 	       C++ Standard Libary		 std::destroy(3)

NAME
     std::destroy - std::destroy

Synopsis
	Defined in header <memory>
	template<		 class		      ForwardIt 	       >
     (since C++17)
	void	 destroy(     ForwardIt     first,     ForwardIt     last     );
     (until C++20)
	template<		 class		      ForwardIt 	       >
     (since C++20)
	constexpr void destroy( ForwardIt first, ForwardIt last );     (1)
	template< class ExecutionPolicy, class ForwardIt >
	void destroy( ExecutionPolicy&& policy, ForwardIt  first,	     (2)
     (since C++17)
	ForwardIt last );

	1) Destroys the objects in the range [first, last), as if by

      for (; first != last; ++first)
	  std::destroy_at(std::addressof(*first));

	2) Same as (1), but executed according to policy. This overload partici-
     pates in
	overload resolution only if

	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)

Parameters
	first, last	     -	       the range of elements to destroy
	policy		      - 	 the execution policy to use. See execu-
     tion policy for
				       details.

Type requirements
	-
	ForwardIt must meet the requirements of LegacyForwardIterator.
	-
	No increment, assignment, comparison, or indirection through  valid  in-
     stances of
	ForwardIt may throw exceptions.

Return value
	(none)

Complexity
	Linear in the distance between first and last.

Exceptions
	The overload with a template parameter named ExecutionPolicy reports er-
     rors 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-de-
     fined.
	  * If the algorithm fails to allocate memory, std::bad_alloc is thrown.

Possible implementation
	template<class ForwardIt>
	constexpr // since C++20
	void destroy(ForwardIt first, ForwardIt last)
	{
	    for (; first != last; ++first)
		std::destroy_at(std::addressof(*first));
	}

Example
	The following example demonstrates how to use destroy to destroy a  con-
     tiguous
	sequence of elements.

     // Run this code

      #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(ptr, ptr + 8);
      }

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

See also
	destroy_n	destroys a number of objects in a range
	(C++17) 	(function template)
	destroy_at	destroys an object at a given address
	(C++17) 	(function template)
	ranges::destroy destroys a range of objects
	(C++20) 	(niebloid)

http://cppreference.com 	   2024.06.10			 std::destroy(3)
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