std::bad_variant_access
Defined in header <variant>
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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
Member functions
(constructor) |
constructs the bad_variant_access object (public member function) |
std::bad_variant_access ::bad_variant_access()
bad_variant_access() noexcept; |
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Constructs a new instance of std::bad_variant_access
.
Parameters
(none)
Inherited from std::exception
Member functions
[virtual] |
destroys the exception object (virtual public member function of std::exception ) |
[virtual] |
returns an explanatory string (virtual public member function of std::exception ) |
Example
Run this code
#include <variant> #include <iostream> 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
See also
(C++17) |
reads the value of the variant given the index or the type (if the type is unique), throws on error (function template) |
(C++17) |
calls the provided functor with the arguments held by one or more variants (function template) |