std::bad_typeid

 

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Type trait constants
integral_constant (C++11)

 

std::bad_typeid

Member functions

bad_typeid::bad_typeid

Inherited from std::exception

exception::~exception

exception::what

 

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

An exception of this type is thrown when a typeid operator is applied to a dereferenced null pointer value of a polymorphic type.

Inheritance diagram

Member functions

(constructor)

constructs a new bad_typeid object (public member function)

Inherited from std::exception

Member functions

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

Example

Run this code

#include <iostream>
#include <typeinfo>
 
struct S { // The type has to be polymorphic
    virtual void f();
}; 
 
int main()
{
    S* p = nullptr;
    try {
        std::cout << typeid(*p).name() << '\n';
    } catch(const std::bad_typeid& e) {
        std::cout << e.what() << '\n';
    }
}

Output:

Attempted a typeid of NULL pointer!