std::ios_base_failure - Man Page

failure (const char *__s, const error_code &=error_code{})
failure (const string &__s, const error_code &) noexcept
failure (const string &__str)  throw ()
error_code code () const noexcept
virtual const char * what () const  throw ()

Returns a C-style character string describing the general cause of the current error.

Reimplemented from std::exception.