std::bad_typeid

From cppreference.com
 
 
 
Type support
Basic types
Fundamental types
Fixed width integer types (C++11)
Numeric limits
numeric_limits
C numeric limits interface
Runtime type information
bad_typeid
bad_cast
Type traits
Primary type categories
is_void (C++11)
is_array (C++11)
is_pointer (C++11)
is_enum (C++11)
is_union (C++11)
is_class (C++11)
is_function (C++11)
is_object (C++11)
is_scalar (C++11)
is_compound (C++11)
is_integral (C++11)
is_floating_point (C++11)
is_fundamental (C++11)
is_arithmetic (C++11)
is_reference (C++11)
is_lvalue_reference (C++11)
is_rvalue_reference (C++11)
is_member_pointer (C++11)
is_member_object_pointer (C++11)
is_member_function_pointer (C++11)
Type properties
is_const (C++11)
is_volatile (C++11)
is_pod (C++11)
is_empty (C++11)
is_polymorphic (C++11)
is_abstract (C++11)
Supported operations
is_constructible
is_trivially_constructible
is_nothrow_constructible
(C++11)
(C++11)
(C++11)
is_default_constructible
is_trivially_default_constructible
is_nothrow_default_constructible
(C++11)
(C++11)
(C++11)
is_copy_constructible
is_trivially_copy_constructible
is_nothrow_copy_constructible
(C++11)
(C++11)
(C++11)
is_move_constructible
is_trivially_move_constructible
is_nothrow_move_constructible
(C++11)
(C++11)
(C++11)
is_assignable
is_trivially_assignable
is_nothrow_assignable
(C++11)
(C++11)
(C++11)
is_copy_assignable
is_trivially_copy_assignable
is_nothrow_copy_assignable
(C++11)
(C++11)
(C++11)
is_move_assignable
is_trivially_move_assignable
is_nothrow_move_assignable
(C++11)
(C++11)
(C++11)
is_destructible
is_trivially_destructible
is_nothrow_destructible
(C++11)
(C++11)
(C++11)
has_virtual_destructor (C++11)
Relationships and property queries
is_same (C++11)
is_base_of (C++11)
is_convertible (C++11)
alignment_of (C++11)
rank (C++11)
extent (C++11)
Type modifications
remove_cv
remove_const
remove_volatile
(C++11)
(C++11)
(C++11)
add_cv
add_const
add_volatile
(C++11)
(C++11)
(C++11)
make_signed (C++11)
make_unsigned (C++11)
Type transformations
aligned_storage (C++11)
aligned_union (C++11)
decay (C++11)
enable_if (C++11)
conditional (C++11)
common_type (C++11)
underlying_type (C++11)
result_of (C++11)
Type trait constants
integral_constant (C++11)
 
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

[edit] 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)
[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!