std::bad_variant_access(3)

💅 std::bad_variant_access — NAME 💅

okay so bestie, this is std::bad_variant_access(3) from the C++ Standard Libary manual, and it's giving “exception type with main character energy” ✨🎀.

std::bad_variant_access - std::bad_variant_access

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✨ Synopsis ✨

Defined in header <variant>
class bad_variant_access : public std::exception  (since C++17)

std::bad_variant_access is the type of the exception thrown in the following situations:

• std::get(std::variant) called with an index or type that does not match the currently active alternative.
• std::visit called to visit a variant that is valueless_by_exception.

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🧚 Member functions 🧚

• constructor — constructs a new bad_variant_access object (public member function)
• operator= — replaces the bad_variant_access object (public member function)
• what — returns the explanatory string (public member function)

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🎀 std::bad_variant_access::bad_variant_access 🎀

bad_variant_access() noexcept;                                  (1)
(since C++17)
bad_variant_access( const bad_variant_access& other ) noexcept; (2)
(since C++17)

Constructs a new bad_variant_access object with an implementation-defined null-terminated byte string which is accessible through what().

1. Default constructor.
2. Copy constructor. If *this and other both have dynamic type std::bad_variant_access then std::strcmp(what(), other.what()) == 0.

Parameters

other - another exception object to copy

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💅 std::bad_variant_access::operator= 💅

bad_variant_access& operator=( const bad_variant_access& other )
noexcept;

(since C++17)

Assigns the contents with those of other. If *this and other both have dynamic type std::bad_variant_access then std::strcmp(what(), other.what()) == 0 after assignment.

Parameters

other - another exception object to assign with

Return value

*this

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🦋 std::bad_variant_access::what 🦋

virtual const char* what() const noexcept;  (since C++17)

Returns the explanatory string.

Parameters

(none)

Return value

Pointer to a null-terminated string with explanatory information. The string is suitable for conversion and display as a std::wstring. The pointer is guaranteed to be valid at least until the exception object from which it is obtained is destroyed, or until a non-const member function (e.g. copy assignment operator) on the exception object is called.

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📝 Notes 📝

Implementations are allowed but not required to override what().

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🌈 Inherited from std::exception 🌈

Member functions

• destructor — destroys the exception object [virtual] (virtual public member function of std::exception)
• what — returns an explanatory string [virtual] (virtual public member function of std::exception)

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🧪 Example 🧪

// Run this code

#include <iostream>
#include <variant>

int main()
{
    std::variant<int, float> v;
    v = 12;
    try
    {
        std::get<float>(v);
    }
    catch (const std::bad_variant_access& e)
    {
        std::cout << e.what() << '\n';
    }
}

✨ Possible output ✨

bad_variant_access

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👀 See also 👀

• get(std::variant) — reads the value of the variant given the index or the type (if the type is unique), throws on error (function template) (C++17)
• visit — calls the provided functor with the arguments held by one or more variants (function template) (C++17)

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mwah 💋 that's the whole page, bestie. source: http://cppreference.com, version/date: 2024.06.10, page: std::bad_variant_access(3) 🫶✨