template<typename _CharT, typename _Traits>
class std::basic_istream< _CharT, _Traits >::sentry
Performs setup work for input streams.
Objects of this class are created before all of the standard extractors are run. It is responsible for exception-safe prefix and suffix operations, although only prefix actions are currently required by the standard.
Definition at line 686 of file istream.
template<typename _CharT , typename _Traits >
The constructor performs all the work.
- Parameters
-
| __is | The input stream to guard. |
| __noskipws | Whether to consume whitespace or not. |
If the stream state is good (__is.good() is true), then the following actions are performed, otherwise the sentry state is false (not okay) and failbit is set in the stream state.
The sentry's preparatory actions are:
- if the stream is tied to an output stream,
is.tie()->flush() is called to synchronize the output sequence
- if __noskipws is false, and
ios_base::skipws is set in is.flags(), the sentry extracts and discards whitespace characters from the stream. The currently imbued locale is used to determine whether each character is whitespace.
If the stream state is still good, then the sentry state becomes true (okay).
Definition at line 46 of file istream.tcc.
References std::ios_base::badbit, std::ios_base::eofbit, std::ios_base::failbit, std::ios_base::flags(), std::basic_ios< _CharT, _Traits >::good(), std::ios_base::goodbit, std::__ctype_abstract_base< _CharT >::is(), std::basic_ios< _CharT, _Traits >::rdbuf(), std::basic_ios< _CharT, _Traits >::setstate(), std::basic_streambuf< _CharT, _Traits >::sgetc(), std::ios_base::skipws, std::basic_streambuf< _CharT, _Traits >::snextc(), and std::basic_ios< _CharT, _Traits >::tie().
1.9.7