std::ranges::destroy - cppreference.com (original) (raw)

Defined in header
Call signature
template< no-throw-input-iterator I, no-throw-sentinel-for<I> S > requires std::destructible<std::iter_value_t<I>> constexpr I destroy( I first, S last ) noexcept;	(1)	(since C++20)
template< no-throw-input-range R > requires std::destructible<ranges::range_value_t<R>> constexpr ranges::borrowed_iterator_t<R> destroy( R&& r ) noexcept;	(2)	(since C++20)

Destroys the objects in the range [first, last), as if by
Same as (1), but uses r as the source range, as if using ranges::begin(r) as first and ranges::end(r) as last.

The function-like entities described on this page are algorithm function objects (informally known as niebloids), that is:

Explicit template argument lists cannot be specified when calling any of them.
None of them are visible to argument-dependent lookup.
When any of them are found by normal unqualified lookup as the name to the left of the function-call operator, argument-dependent lookup is inhibited.

[edit] Parameters

first, last	-	the iterator-sentinel pair defining the range of elements to destroy
r	-	the range to destroy

[edit] Return value

An iterator compares equal to last.

[edit] Complexity

Linear in the distance between first and last.

[edit] Possible implementation

[edit] Example

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

#include #include #include 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::ranges::destroy(ptr, ptr + 8); }

Output:

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