21 Language support library [language.support]

21.7 Type identification [support.rtti]

21.7.3 Class bad_­cast [bad.cast]

namespace std {
  class bad_cast : public exception {
  public:
    bad_cast() noexcept;
    bad_cast(const bad_cast&) noexcept;
    bad_cast& operator=(const bad_cast&) noexcept;
    const char* what() const noexcept override;
  };
}
The class bad_­cast defines the type of objects thrown as exceptions by the implementation to report the execution of an invalid dynamic_­cast expression ([expr.dynamic.cast]).
bad_cast() noexcept;
Effects: Constructs an object of class bad_­cast.
bad_cast(const bad_cast&) noexcept; bad_cast& operator=(const bad_cast&) noexcept;
Effects: Copies an object of class bad_­cast.
const char* what() const noexcept override;
Returns: An implementation-defined ntbs.
Remarks: The message may be a null-terminated multibyte string, suitable for conversion and display as a wstring ([string.classes], [locale.codecvt])