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bad_cast

class
<typeinfo> 
class bad_cast;

Exception thrown on failure to dynamic cast

bad_cast

Type of the exceptions thrown by dynamic_cast when they fail the run-time check performed on references to polymorphic class types.

The run-time check fails if the object would be an incomplete object of the destination type.

Its member what returns a null-terminated character sequence identifying the exception.

Some functions in the standard library may also throw this exception to signal a type-casting error.

Example

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// bad_cast example
#include <iostream>
#include <typeinfo>
using namespace std;
class Base {virtual void Member(){}};
class Derived : Base {};
int main () {
  try
  {
    Base b;
    Derived& rd = dynamic_cast<Derived&>(b);
  }
  catch (bad_cast& bc)
  {
     cerr << "bad_cast caught: " << bc.what() << endl;
  }
  return 0;
}


Possible output:

bad_cast caught: St8bad_cast

See also

exception Standard exception class (class)