Defined in header <istream> | ||
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template< class CharT, class Traits = std::char_traits<CharT> > class basic_istream : virtual public std::basic_ios<CharT, Traits> |
The class template basic_istream
provides support for high level input operations on character streams. The supported operations include formatted input (e.g. integer values or whitespace-separated characters and characters strings) and unformatted input (e.g. raw characters and character arrays). This functionality is implemented in terms of the interface provided by the underlying basic_streambuf
class, accessed through the basic_ios
base class. The only non-inherited data member of basic_istream
, in most implementations, is the value returned by basic_istream::gcount()
.
Inheritance diagram.
Two specializations for common character types are defined:
Defined in header <istream> |
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Type | Definition |
istream | basic_istream<char> |
wistream | basic_istream<wchar_t> |
Two global basic_istream objects are provided by the standard library.
Defined in header <iostream> |
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reads from the standard C input stream stdin (global object) |
Member type | Definition |
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char_type | CharT
|
traits_type | Traits ; the program is ill-formed if Traits::char_type is not CharT . |
int_type | Traits::int_type
|
pos_type | Traits::pos_type
|
off_type | Traits::off_type
|
constructs the object (public member function) |
|
[virtual] | destructs the object (virtual public member function) |
(C++11) | move-assigns from another basic_istream (protected member function) |
Formatted input |
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extracts formatted data (public member function) |
|
Unformatted input |
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extracts characters (public member function) |
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reads the next character without extracting it (public member function) |
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unextracts a character (public member function) |
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puts character into input stream (public member function) |
|
extracts characters until the given character is found (public member function) |
|
extracts and discards characters until the given character is found (public member function) |
|
extracts blocks of characters (public member function) |
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extracts already available blocks of characters (public member function) |
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returns number of characters extracted by last unformatted input operation (public member function) |
|
Positioning |
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returns the input position indicator (public member function) |
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sets the input position indicator (public member function) |
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Miscellaneous |
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synchronizes with the underlying storage device (public member function) |
|
(C++11) | swaps stream objects, except for the associated buffer (protected member function) |
implements basic logic for preparation of the stream for input operations (public member class) |
extracts characters and character arrays (function template) |
Member type | Definition |
---|---|
char_type | CharT |
traits_type | Traits |
int_type | Traits::int_type |
pos_type | Traits::pos_type |
off_type | Traits::off_type |
State functions |
|
checks if no error has occurred i.e. I/O operations are available (public member function of std::basic_ios<CharT,Traits> ) |
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checks if end-of-file has been reached (public member function of std::basic_ios<CharT,Traits> ) |
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checks if an error has occurred (public member function of std::basic_ios<CharT,Traits> ) |
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checks if a non-recoverable error has occurred (public member function of std::basic_ios<CharT,Traits> ) |
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checks if an error has occurred (synonym of fail() ) (public member function of std::basic_ios<CharT,Traits> ) |
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(until C++11)(since C++11) | checks if no error has occurred (synonym of !fail() ) (public member function of std::basic_ios<CharT,Traits> ) |
returns state flags (public member function of std::basic_ios<CharT,Traits> ) |
|
sets state flags (public member function of std::basic_ios<CharT,Traits> ) |
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modifies state flags (public member function of std::basic_ios<CharT,Traits> ) |
|
Formatting |
|
copies formatting information (public member function of std::basic_ios<CharT,Traits> ) |
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manages the fill character (public member function of std::basic_ios<CharT,Traits> ) |
|
Miscellaneous |
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manages exception mask (public member function of std::basic_ios<CharT,Traits> ) |
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sets the locale (public member function of std::basic_ios<CharT,Traits> ) |
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manages associated stream buffer (public member function of std::basic_ios<CharT,Traits> ) |
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manages tied stream (public member function of std::basic_ios<CharT,Traits> ) |
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narrows characters (public member function of std::basic_ios<CharT,Traits> ) |
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widens characters (public member function of std::basic_ios<CharT,Traits> ) |
Formatting |
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manages format flags (public member function of std::ios_base ) |
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sets specific format flag (public member function of std::ios_base ) |
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clears specific format flag (public member function of std::ios_base ) |
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manages decimal precision of floating point operations (public member function of std::ios_base ) |
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manages field width (public member function of std::ios_base ) |
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Locales |
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sets locale (public member function of std::ios_base ) |
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returns current locale (public member function of std::ios_base ) |
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Internal extensible array |
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[static] | returns a program-wide unique integer that is safe to use as index to pword() and iword() (public static member function of std::ios_base ) |
resizes the private storage if necessary and access to the long element at the given index (public member function of std::ios_base ) |
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resizes the private storage if necessary and access to the void* element at the given index (public member function of std::ios_base ) |
|
Miscellaneous |
|
registers event callback function (public member function of std::ios_base ) |
|
[static] | sets whether C++ and C IO libraries are interoperable (public static member function of std::ios_base ) |
Member classes |
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stream exception (public member class of std::ios_base ) |
|
initializes standard stream objects (public member class of std::ios_base ) |
Member types and constants |
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Type | Explanation | ||||||||||||||||||||||||||||||||||||||
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stream open mode type The following constants are also defined:
(typedef) |
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formatting flags type The following constants are also defined:
(typedef) |
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state of the stream type The following constants are also defined:
(typedef) |
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seeking direction type The following constants are also defined:
(typedef) |
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specifies event type (enum) |
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callback function type (typedef) |
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