std::basic_istream< _CharT, _Traits >::sentry Class Reference

Performs setup work for input streams. More...

List of all members.

Public Types
typedef _Traits	traits_type
	Easy access to dependant types.
typedef basic_streambuf< _CharT, _Traits >	__streambuf_type
typedef basic_istream< _CharT, _Traits >	__istream_type
typedef __istream_type::__ctype_type	__ctype_type
typedef _Traits::int_type	__int_type
Public Member Functions
	sentry (basic_istream< _CharT, _Traits > &__is, bool __noskipws=false)
	The constructor performs all the work.
	operator bool () const
	Quick status checking.
Private Attributes
bool	_M_ok

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Detailed Description

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. Additional actions may be added by the implementation, and we list them in http://gcc.gnu.org/onlinedocs/libstdc++/17_intro/howto.html#5 under [27.6] notes.

Definition at line 579 of file istream.

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Member Typedef Documentation

template<typename _CharT, typename _Traits> typedef __istream_type::__ctype_type std::basic_istream< _CharT, _Traits >::sentry::__ctype_type

Definition at line 586 of file istream.

template<typename _CharT, typename _Traits> typedef _Traits::int_type std::basic_istream< _CharT, _Traits >::sentry::__int_type

Definition at line 587 of file istream.

template<typename _CharT, typename _Traits> typedef basic_istream<_CharT, _Traits> std::basic_istream< _CharT, _Traits >::sentry::__istream_type

Definition at line 585 of file istream.

template<typename _CharT, typename _Traits> typedef basic_streambuf<_CharT, _Traits> std::basic_istream< _CharT, _Traits >::sentry::__streambuf_type

Definition at line 584 of file istream.

template<typename _CharT, typename _Traits> typedef _Traits std::basic_istream< _CharT, _Traits >::sentry::traits_type

Easy access to dependant types. Definition at line 583 of file istream.

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Constructor & Destructor Documentation

template<typename _CharT, typename _Traits> std::basic_istream< _CharT, _Traits >::sentry::sentry (  basic_istream< _CharT, _Traits > &  __is, bool  __noskipws = false )  [explicit]

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 47 of file istream.tcc. References std::__check_facet(), std::basic_ios< _CharT, _Traits >::_M_ctype, std::ios_base::flags(), std::basic_ios< _CharT, _Traits >::good(), std::ios_base::iostate, std::basic_ios< _CharT, _Traits >::rdbuf(), std::basic_ios< _CharT, _Traits >::setstate(), and std::basic_ios< _CharT, _Traits >::tie().

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Member Function Documentation

template<typename _CharT, typename _Traits> std::basic_istream< _CharT, _Traits >::sentry::operator bool (   )  const [inline]

Quick status checking. Returns: The sentry state. For ease of use, sentries may be converted to booleans. The return value is that of the sentry state (true == okay). Definition at line 620 of file istream.

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Member Data Documentation

template<typename _CharT, typename _Traits> bool std::basic_istream< _CharT, _Traits >::sentry::_M_ok [private]

Definition at line 623 of file istream.

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The documentation for this class was generated from the following files:

• istream
• istream.tcc

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