std::raw_storage_iterator
<memory>
class raw_storage_iterator
class raw_storage_iterator;
(deprecated in C++17)
(removed in C++20)
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 LegacyOutputIterator 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.
[edit] Type requirements
OutputIt must meet the requirements of LegacyOutputIterator.
[edit] Member functions
[edit] Member types
iterator_category
std::output_iterator_tag
value_type
void
pointer
void
reference
void
Member types iterator_category, value_type, difference_type, pointer and reference are required to be obtained by inheriting from std::iterator <std::output_iterator_tag, void, void, void, void>.
[edit] Note
std::raw_storage_iterator was deprecated primarily because of its exception-unsafe behavior. Unlike std::uninitialized_copy , it doesn't handle exceptions during operations like std::copy safely, potentially leading to resource leaks due to a lack of tracking the number of successfully constructed objects and their proper destruction in the presence of exceptions.
[edit] Example
#include <algorithm> #include <iostream> #include <memory> #include <string> int main() { const std::string s[] = {"This", "is", "a", "test", "."}; std::string * p = std::allocator <std::string >().allocate(5); 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::allocator <std::string >().deallocate(p, 5); }
Output:
This is a test .