This exception will be thrown from an API function that, from a C perspective,
would result in a CONFD_ERR return value.
Available attributes:
confd_errno -- the underlying error number
confd_strerror -- string representation of the confd_errno
confd_lasterr -- string with additional textual information
strerror -- os error string (available if confd_errno is CONFD_ERR_OS)