18 Language support library [language.support]

18.7 Type identification [support.rtti]

18.7.3 Class bad_typeid [bad.typeid]

namespace std {
  class bad_typeid : public exception {
  public:
    bad_typeid() noexcept;
    bad_typeid(const bad_typeid&) noexcept;
    bad_typeid& operator=(const bad_typeid&) noexcept;
    virtual const char* what() const noexcept;
  };
}

The class bad_typeid defines the type of objects thrown as exceptions by the implementation to report a null pointer in a typeid expression ([expr.typeid]).

bad_typeid() noexcept;

Effects: Constructs an object of class bad_typeid.

Remarks: The result of calling what() on the newly constructed object is implementation-defined.

bad_typeid(const bad_typeid&) noexcept; bad_typeid& operator=(const bad_typeid&) noexcept;

Effects: Copies an object of class bad_typeid.

virtual const char* what() const noexcept;

Returns: An implementation-defined ntbs.

Remarks: The message may be a null-terminated multibyte string ([multibyte.strings]), suitable for conversion and display as a wstring ([string.classes], [locale.codecvt])