std::bad_typeid

Defined in header <typeinfo>

1	`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

#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:

1	`Attempted a` `typeid` `of NULL pointer!`

Links:

http://en.cppreference.com/w/cpp/types/bad_typeid

doc_CPP

2025-01-10 15:47:30

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