ios_base::iostate
typedef T2 iostate;
static const iostate badbit, eofbit, failbit, goodbit;
The type is an enumerated type T2 that describes an object that can store stream state information. The distinct flag values are:
- badbit, to record a loss of integrity of the stream buffer
 - eofbit, to record end-of-file while extracting from a stream
 - failbit, to record a failure to extract a valid field from a stream
 
In addition, a useful value is:
- goodbit, no bits set