NAME¶

std::return_temporary_buffer - std::return_temporary_buffer

Synopsis¶

Defined in header <memory>
template< class T > (deprecated in C++17)
void return_temporary_buffer( T* p ); (removed in C++20)

Deallocates the storage referenced by p.

If p is not a pointer value returned by an earlier call to
std::get_temporary_buffer, or has been invalidated by an intervening
std::return_temporary_buffer call, the behavior is undefined.

Parameters¶

p - the pointer referring to the storage to be declloated

Return value¶

(none)

Exceptions¶

Throws nothing.

Example¶

// Run this code

#include <algorithm>
#include <iostream>
#include <iterator>
#include <memory>
#include <string>

int main()
{
const std::string s[] = {"string", "1", "test", "..."};
const auto p = std::get_temporary_buffer<std::string>(4);
// requires that p.first is passed to return_temporary_buffer
// (beware of early exit points and exceptions), or better use:
std::unique_ptr<std::string, void(*)(std::string*)> on_exit(p.first,
[](std::string* p)
{
std::cout << "returning temporary buffer...\n";
std::return_temporary_buffer(p);
});

std::copy(s, s + p.second,
std::raw_storage_iterator<std::string*, std::string>(p.first));
// has same effect as: std::uninitialized_copy(s, s + p.second, p.first);
// requires that each string in p is individually destroyed
// (beware of early exit points and exceptions)

std::copy(p.first, p.first + p.second,
std::ostream_iterator<std::string>{std::cout, "\n"});

std::for_each(p.first, p.first + p.second, [](std::string& e)
{
e.~basic_string<char>();
}); // same as: std::destroy(p.first, p.first + p.second);

// manually reclaim memory if unique_ptr-like technique is not used:
// std::return_temporary_buffer(p.first);
}

Output:¶

string
1
test
...
returning temporary buffer...

Defect reports

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

DR Applied to Behavior as published Correct behavior
the storage allocated by the behavior is
LWG 2072 C++98 std::get_temporary_buffer undefined in this
could be deallocated multiple times case

See also¶

get_temporary_buffer obtains uninitialized storage
(deprecated in C++17) (function template)
(removed in C++20)