std::move_iterator<Iter>::operator*,->
From cppreference.com
< cpp | iterator | move iterator
reference operator*() const; |
(1) | (since C++11) (constexpr since C++17) |
pointer operator->() const; |
(2) | (since C++11) (constexpr since C++17) (deprecated in C++20) |
Returns an rvalue reference or pointer to the current element.
Return value
2)
current
Notes
operator-> is deprecated because deferencing its result may yield an lvalue. This may lead to unintended behavior.
Example
Run this code
#include <iomanip> #include <iostream> #include <iterator> #include <string> #include <vector> void print(auto rem, const auto& v) { for (std::cout << rem; const auto& e : v) std::cout << std::quoted(e) << ' '; std::cout << '\n'; } int main() { std::vector<std::string> p{"alpha", "beta", "gamma", "delta"}, q; print("1) p: ", p); for (std::move_iterator it{p.begin()}, end{p.end()}; it != end; ++it) { it->push_back('!'); // calls -> string::push_back(char) q.emplace_back(*it); // *it <- overload (1) } print("2) p: ", p); print("3) q: ", q); std::vector v{1, 2, 3}; std::move_iterator it{v.begin()}; // *it = 13; // error: using rvalue as lvalue }
Possible output:
1) p: "alpha" "beta" "gamma" "delta" 2) p: "" "" "" "" 3) q: "alpha!" "beta!" "gamma!" "delta!"
Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
DR | Applied to | Behavior as published | Correct behavior |
---|---|---|---|
LWG 2106 | C++11 | operator* would return a dangling reference if * current yields a prvalue
|
returns the object in this case |
See also
(C++11) |
accesses an element by index (public member function) |