Namespaces
Variants
Views
Actions

std::bad_typeid

From cppreference.com
< cpp‎ | types
Revision as of 20:04, 31 May 2013 by P12bot (Talk | contribs)

 
 
 
Type support
Basic types
Fundamental types
Fixed width integer types (C++11)
Numeric limits
C numeric limits interface
Runtime type information
bad_typeid
Type traits
Primary type categories
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
Type properties
(C++11)
(C++11)
(C++11)
(C++14)
Supported operations
Relationships and property queries
(C++11)
(C++11)
(C++11)
(C++11)
Type modifications
(C++11)(C++11)(C++11)
Type transformations
(C++11)
(C++11)
(C++11)
Type trait constants
 
std::bad_typeid
 
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 or a polymorphic type.

cpp/error/exceptionstd-bad typeid-inheritance.svg
About this image

Inheritance diagram

Contents

Member functions

constructs a new bad_typeid object
(public member function)

Inherited from std::exception

Member functions

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

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:

Attempted a typeid of NULL pointer!