std::raw_storage_iterator

 

C++

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Technical Specifications

 

Dynamic memory management

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raw_storage_iterator
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Low level memory management

 

std::raw_storage_iterator

Member functions

raw_storage_iterator::raw_storage_iterator

raw_storage_iterator::operator=

raw_storage_iterator::operator*

raw_storage_iterator::base (C++17)

raw_storage_iterator::operator++raw_storage_iterator::operator++(int)

 

Defined in header <memory>
template< class OutputIt, class T > class raw_storage_iterator     : public std::iterator<std::output_iterator_tag, void, void, void, void>;		(until C++17)
template< class OutputIt, class T > class raw_storage_iterator;		(since C++17)

The output iterator std::raw_storage_iterator makes it possible for standard algorithms to store results in uninitialized memory. Whenever the algorithm writes an object of type T to the dereferenced iterator, the object is copy-constructed into the location in the uninitialized storage pointed to by the iterator. The template parameter OutputIt is any type that meets the requirements of OutputIterator and has operator* defined to return an object, for which operator& returns an object of type T*. Usually, the type T* is used as OutputIt.

Type requirements

- OutputIt must meet the requirements of OutputIterator.

Member functions

(constructor)	creates a new raw_storage_iterator (public member function)
operator=	constructs an object at the pointed-to location in the buffer (public member function)
operator*	dereferences the iterator (public member function)
operator++operator++(int)	advances the iterator (public member function)
base (since C++17)	provides access to the wrapped iterator (public member function)

Member types

Member type	Definition
value_type	void
difference_type	void
pointer	void
reference	void
iterator_category	std::output_iterator_tag

Note: before C++17, these member types are required to be obtained by inheriting from std::iterator<std::output_iterator_tag,void,void,void,void>.

Example

Run this code

#include <iostream>
#include <string>
#include <memory>
#include <algorithm>
 
int main()
{
    const std::string s[] = {"This", "is", "a", "test", "."};
    std::string* p = std::get_temporary_buffer<std::string>(5).first;
 
    std::copy(std::begin(s), std::end(s),
              std::raw_storage_iterator<std::string*, std::string>(p));
 
    for(std::string* i = p; i!=p+5; ++i) {
        std::cout << *i << '\n';
        i->~basic_string<char>();
    }
    std::return_temporary_buffer(p);
}

Output:

This
is
a
test
.

See also

allocator_traits (C++11)	provides information about allocator types (class template)
scoped_allocator_adaptor (C++11)	implements multi-level allocator for multi-level containers (class template)
uses_allocator (C++11)	checks if the specified type supports uses-allocator construction (class template)