std::optional<T>:: operator->, std::optional<T>:: operator*

Accesses the contained value.

Return value

Notes

This operator does not check whether * this contains a value, users can do so manually by using has_value() or operator bool() . Alternatively, if checked access is needed, value() or value_or() may be used.

Example

#include <iomanip>
#include <iostream>
#include <optional>
#include <string>
int main()
{
    using namespace std::string_literals;
    std::optional<int> opt1{1};
    std::cout << "opt1: " << *opt1 << '\n';
    *opt1 = 2;
    std::cout << "opt1: " << *opt1 << '\n';
    std::optional<std::string> opt2{"abc"s};
    std::cout << "opt2: " << std::quoted(*opt2) << ", size: " << opt2->size() << '\n';
    // You can “take” the contained value by calling operator* on an rvalue to optional
    auto taken = *std::move(opt2);
    std::cout << "taken: " << std::quoted(taken) << "\n"
                 "opt2: " << std::quoted(*opt2) << ", size: " << opt2->size() << '\n';
}

opt1: 1
opt1: 2
opt2: "abc", size: 3
taken: "abc"
opt2: "", size: 0

Defect reports

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

See also