basic_istream::sentry

The nested class describes an object whose declaration structures the formatted and unformatted input functions.

class sentry {
public:
      explicit sentry(
           basic_istream<Elem, Tr>& _Istr,
         bool _Noskip = false
     );
     operator bool( ) const;
};

Remarks

If _Istr.good is true, the constructor:

• Calls _Istr.tie -> flush if _Istr.tie is not a null pointer

• Effectively calls ws(_Istr) if _Istr.flags & skipws is nonzero

If, after any such preparation, _Istr.good is false, the constructor calls _Istr.setstate(failbit). In any case, the constructor stores the value returned by _Istr.good in status. A later call to operator bool delivers this stored value.

Requirements

Header: <istream>

Namespace: std

See Also

Concepts

basic_istream Class

basic_istream Members

iostream Programming

iostreams Conventions