std::bad_variant_access (3) - Linux Manuals

std::bad_variant_access: std::bad_variant_access

NAME

std::bad_variant_access - std::bad_variant_access

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

Member functions

              constructs the bad_variant_access object
constructor (public member function)

 std::bad_variant_access ::bad_variant_access()

bad_variant_access() noexcept;

Constructs a new instance of std::bad_variant_access.

Parameters

(none)

Inherited from std::exception

Member functions

destructor destroys the exception object
             (virtual public member function of std::exception)
[virtual]

what returns an explanatory string
             (virtual public member function of std::exception)
[virtual]

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