std::experi...onal::value(3)

💖 std::experimental::optional::value 💖

okay bestie, this one comes straight from the C++ Standard Library (specifically the library fundamentals TS, iykyk) and it’s the checked-access icon of std::experimental::optional. ✨

🌸 NAME 🌸

std::experimental::optional::value — std::experimental::optional::value

yes, the page title and the NAME line are literally twins. no cap. 💅

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✨ Synopsis ✨

constexpr T& value() &;               (1) (library fundamentals TS)
constexpr const T & value() const &;
constexpr T&& value() &&;             (2) (library fundamentals TS)
constexpr const T&& value() const &&;

Returns the contained value. 💖

1. Equivalent to return bool(*this) ? *val : throw bad_optional_access();.
2. Equivalent to return bool(*this) ? std::move(*val) : throw bad_optional_access();.

🎀 Parameters 🎀

(none) — she takes no arguments, bestie. literally none. 💀

🦋 Return value 🦋

A reference to the contained value. 🫶

🌈 Exceptions 🌈

std::experimental::bad_optional_access if *this does not contain a value. 😭

okay so if the optional is empty, value() does not play nice — she throws. checked access, periodt.

⭐ Notes ⭐

The dereference operator operator*() does not check if this optional contains a value, which may be more efficient than value(). 👑

🍓 Example 🍓

// Run this code

#include <experimental/optional>
#include <iostream>

int main()
{
    std::experimental::optional<int> opt = {};

    try
    {
        int n = opt.value();
    }
    catch (const std::logic_error& e)
    {
        std::cout << e.what() << '\n';
    }
}

Possible output:

optional<T>::value: not engaged

🔥 See also 🔥

• value_or — returns the contained value if available, another value otherwise (public member function)
• operator->, operator* — accesses the contained value (public member function)
• bad_optional_access (library fundamentals TS) — exception indicating checked access to an optional that doesn’t contain a value (class)

🏷️ Category 🏷️

• Category: Noindexed pages

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mwah 💋 — this was std::experi...onal::value(3) from http://cppreference.com, dated 2024.06.10. source/version vibes, locked in. 🎀✨