std::basic_iostream - cppreference.com (original) (raw)

| | | | | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | | | template< class CharT, class Traits = std::char_traits<CharT> > class basic_iostream : public basic_istream<CharT, Traits>, public basic_ostream<CharT, Traits> | | |

The class template basic_iostream provides support for high level input/output operations on streams. The supported operations include sequential reading or writing and formatting. This functionality is implemented over the interface provided by the std::basic_streambuf class. It is accessed through std::basic_ios class.

std-basic iostream-inheritance.svg

Inheritance diagram

Several typedefs for common character types are provided:
Type Definition
std::iostream std::basic_iostream<char>
std::wiostream std::basic_iostream<wchar_t>

Contents

[edit] Member types

Member type Definition
char_type CharT[edit]
traits_type Traits; the program is ill-formed if Traits::char_type is not CharT.[edit]
int_type Traits::int_type[edit]
pos_type Traits::pos_type[edit]
off_type Traits::off_type[edit]

[edit] Member functions

[edit] Protected member functions

| | move-assigns another basic_iostream (protected member function) [edit] | | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | | exchanges the state with another basic_iostream (public member function) [edit] |

Inherited from std::basic_istream

Member functions

Formatted input
operator>> extracts formatted data (public member function of std::basic_istream<CharT,Traits>) [edit]
Unformatted input
get extracts characters (public member function of std::basic_istream<CharT,Traits>) [edit]
peek reads the next character without extracting it (public member function of std::basic_istream<CharT,Traits>) [edit]
unget unextracts a character (public member function of std::basic_istream<CharT,Traits>) [edit]
putback puts a character into input stream (public member function of std::basic_istream<CharT,Traits>) [edit]
getline extracts characters until the given character is found (public member function of std::basic_istream<CharT,Traits>) [edit]
ignore extracts and discards characters until the given character is found (public member function of std::basic_istream<CharT,Traits>) [edit]
read extracts blocks of characters (public member function of std::basic_istream<CharT,Traits>) [edit]
readsome extracts already available blocks of characters (public member function of std::basic_istream<CharT,Traits>) [edit]
gcount returns number of characters extracted by last unformatted input operation (public member function of std::basic_istream<CharT,Traits>) [edit]
Positioning
tellg returns the input position indicator (public member function of std::basic_istream<CharT,Traits>) [edit]
seekg sets the input position indicator (public member function of std::basic_istream<CharT,Traits>) [edit]
Miscellaneous
sync synchronizes with the underlying storage device (public member function of std::basic_istream<CharT,Traits>) [edit]

Member classes

| | implements basic logic for preparation of the stream for input operations (public member class of std::basic_istream<CharT,Traits>) [edit] | | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |

Inherited from std::basic_ostream

Member functions

Formatted output
operator<< inserts formatted data (public member function of std::basic_ostream<CharT,Traits>) [edit]
Unformatted output
put inserts a character (public member function of std::basic_ostream<CharT,Traits>) [edit]
write inserts blocks of characters (public member function of std::basic_ostream<CharT,Traits>) [edit]
Positioning
tellp returns the output position indicator (public member function of std::basic_ostream<CharT,Traits>) [edit]
seekp sets the output position indicator (public member function of std::basic_ostream<CharT,Traits>) [edit]
Miscellaneous
flush synchronizes with the underlying storage device (public member function of std::basic_ostream<CharT,Traits>) [edit]

Member classes

| | implements basic logic for preparation of the stream for output operations (public member class of std::basic_ostream<CharT,Traits>) [edit] | | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |

Inherited from std::basic_ios

Member types

Member type Definition
char_type CharT
traits_type Traits
int_type Traits::int_type
pos_type Traits::pos_type
off_type Traits::off_type

Member functions

State functions
good checks if no error has occurred i.e. I/O operations are available (public member function of std::basic_ios<CharT,Traits>) [edit]
eof checks if end-of-file has been reached (public member function of std::basic_ios<CharT,Traits>) [edit]
fail checks if an error has occurred (public member function of std::basic_ios<CharT,Traits>) [edit]
bad checks if a non-recoverable error has occurred (public member function of std::basic_ios<CharT,Traits>) [edit]
operator! checks if an error has occurred (synonym of fail()) (public member function of std::basic_ios<CharT,Traits>) [edit]
operator bool checks if no error has occurred (synonym of fail()) (public member function of std::basic_ios<CharT,Traits>) [edit]
rdstate returns state flags (public member function of std::basic_ios<CharT,Traits>) [edit]
setstate sets state flags (public member function of std::basic_ios<CharT,Traits>) [edit]
clear modifies state flags (public member function of std::basic_ios<CharT,Traits>) [edit]
Formatting
copyfmt copies formatting information (public member function of std::basic_ios<CharT,Traits>) [edit]
fill manages the fill character (public member function of std::basic_ios<CharT,Traits>) [edit]
Miscellaneous
exceptions manages exception mask (public member function of std::basic_ios<CharT,Traits>) [edit]
imbue sets the locale (public member function of std::basic_ios<CharT,Traits>) [edit]
rdbuf manages associated stream buffer (public member function of std::basic_ios<CharT,Traits>) [edit]
tie manages tied stream (public member function of std::basic_ios<CharT,Traits>) [edit]
narrow narrows characters (public member function of std::basic_ios<CharT,Traits>) [edit]
widen widens characters (public member function of std::basic_ios<CharT,Traits>) [edit]

Inherited from std::ios_base

Member functions

Formatting
flags manages format flags (public member function of std::ios_base) [edit]
setf sets specific format flag (public member function of std::ios_base) [edit]
unsetf clears specific format flag (public member function of std::ios_base) [edit]
precision manages decimal precision of floating point operations (public member function of std::ios_base) [edit]
width manages field width (public member function of std::ios_base) [edit]
Locales
imbue sets locale (public member function of std::ios_base) [edit]
getloc returns current locale (public member function of std::ios_base) [edit]
Internal extensible array
xalloc[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) [edit]
iword resizes the private storage if necessary and access to the long element at the given index (public member function of std::ios_base) [edit]
pword resizes the private storage if necessary and access to the void* element at the given index (public member function of std::ios_base) [edit]
Miscellaneous
register_callback registers event callback function (public member function of std::ios_base) [edit]
sync_with_stdio[static] sets whether C++ and C I/O libraries are interoperable (public static member function of std::ios_base) [edit]
Member classes
failure stream exception (public member class of std::ios_base) [edit]
Init initializes standard stream objects (public member class of std::ios_base) [edit]

[edit] Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR Applied to Behavior as published Correct behavior
LWG 271 C++98 the member types char_type, traits_type, int_type, pos_type and off_type were not defined(std::basic_istream and std::basic_ostream both define these types, resulted in ambiguity) definethese types

[edit] See also