std::bad_cast (3) - Linux Manuals

std::bad_cast: std::bad_cast


std::bad_cast - std::bad_cast


Defined in header <typeinfo>
class bad_cast : public std::exception;

An exception of this type is thrown when a dynamic_cast to a reference type fails the run-time check (e.g. because the types are not related by inheritance), and also from std::use_facet if the requested facet does not exist in the locale.
 std-bad cast-inheritance.svg
Inheritance diagram

Member functions

              constructs a new bad_cast object
constructor (public member function)

Inherited from std::exception

Member functions

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

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


// Run this code

  #include <iostream>
  #include <typeinfo>

  struct Foo { virtual ~Foo() {} };
  struct Bar { virtual ~Bar() {} };

  int main()
      Bar b;
      try {
          Foo& f = dynamic_cast<Foo&>(b);
      } catch(const std::bad_cast& e)
          std::cout << e.what() << '\n';

Possible output:

  Bad dynamic cast