std::basic_iostream(3)

NAME
std::basic_iostream - std::basic_iostream

Synopsis
   Defined in header <istream>
   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:
   Defined in header <istream>
   Type Definition
   std::iostream std::basic_iostream<char>
   std::wiostream std::basic_iostream<wchar_t>

Member types
   Member type Definition
   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

Member functions
   constructor constructs the object
                 (public member function)
   destructor destructs the object
   [virtual] (virtual public member function)

Protected member functions
   operator= move-assigns another basic_iostream
   (C++11) (protected member function)
   swap exchanges the state with another basic_iostream
   (C++11) (public member function) Inherited from std::basic_istream

Member functions

Formatted input
   operator>> extracts formatted data
              (public member function of std::basic_istream<CharT,Traits>)

Unformatted input
   get extracts characters
              (public member function of std::basic_istream<CharT,Traits>)
   peek reads the next character without extracting it
              (public member function of std::basic_istream<CharT,Traits>)
   unget unextracts a character
              (public member function of std::basic_istream<CharT,Traits>)
   putback puts a character into input stream
              (public member function of std::basic_istream<CharT,Traits>)
   getline extracts characters until the given character is found
              (public member function of std::basic_istream<CharT,Traits>)
   ignore extracts and discards characters until the given character is found
              (public member function of std::basic_istream<CharT,Traits>)
   read extracts blocks of characters
              (public member function of std::basic_istream<CharT,Traits>)
   readsome extracts already available blocks of characters
              (public member function of std::basic_istream<CharT,Traits>)
              returns number of characters extracted by last unformatted input
   gcount operation
              (public member function of std::basic_istream<CharT,Traits>)

Positioning
   tellg returns the input position indicator
              (public member function of std::basic_istream<CharT,Traits>)
   seekg sets the input position indicator
              (public member function of std::basic_istream<CharT,Traits>)

Miscellaneous
   sync synchronizes with the underlying storage device
              (public member function of std::basic_istream<CharT,Traits>)

Member classes
   sentry implements basic logic for preparation of the stream for input operations
          (public member class of std::basic_istream<CharT,Traits>) Inherited from std::basic_ostream

Member functions

Formatted output
   operator<< inserts formatted data
              (public member function of std::basic_ostream<CharT,Traits>)

Unformatted output
   put inserts a character
              (public member function of std::basic_ostream<CharT,Traits>)
   write inserts blocks of characters
              (public member function of std::basic_ostream<CharT,Traits>)

Positioning
   tellp returns the output position indicator
              (public member function of std::basic_ostream<CharT,Traits>)
   seekp sets the output position indicator
              (public member function of std::basic_ostream<CharT,Traits>)

Miscellaneous
   flush synchronizes with the underlying storage device
              (public member function of std::basic_ostream<CharT,Traits>)

Member classes
   sentry implements basic logic for preparation of the stream for output operations
          (public member class of std::basic_ostream<CharT,Traits>) 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>)
   eof checks if end-of-file has been reached
                 (public member function of std::basic_ios<CharT,Traits>)
   fail checks if an error has occurred
                 (public member function of std::basic_ios<CharT,Traits>)
   bad checks if a non-recoverable error has occurred
                 (public member function of std::basic_ios<CharT,Traits>)
   operator! checks if an error has occurred (synonym of fail())
                 (public member function of std::basic_ios<CharT,Traits>)
   operator bool checks if no error has occurred (synonym of !fail())
                 (public member function of std::basic_ios<CharT,Traits>)
   rdstate returns state flags
                 (public member function of std::basic_ios<CharT,Traits>)
   setstate sets state flags
                 (public member function of std::basic_ios<CharT,Traits>)
   clear modifies state flags
                 (public member function of std::basic_ios<CharT,Traits>)

Formatting
   copyfmt copies formatting information
                 (public member function of std::basic_ios<CharT,Traits>)
   fill manages the fill character
                 (public member function of std::basic_ios<CharT,Traits>)

Miscellaneous
   exceptions manages exception mask
                 (public member function of std::basic_ios<CharT,Traits>)
   imbue sets the locale
                 (public member function of std::basic_ios<CharT,Traits>)
   rdbuf manages associated stream buffer
                 (public member function of std::basic_ios<CharT,Traits>)
   tie manages tied stream
                 (public member function of std::basic_ios<CharT,Traits>)
   narrow narrows characters
                 (public member function of std::basic_ios<CharT,Traits>)
   widen widens characters
                 (public member function of std::basic_ios<CharT,Traits>) Inherited from std::ios_base

Member functions

Formatting
   flags manages format flags
                     (public member function of std::ios_base)
   setf sets specific format flag
                     (public member function of std::ios_base)
   unsetf clears specific format flag
                     (public member function of std::ios_base)
   precision manages decimal precision of floating point operations
                     (public member function of std::ios_base)
   width manages field width
                     (public member function of std::ios_base)

Locales
   imbue sets locale
                     (public member function of std::ios_base)
   getloc returns current locale
                     (public member function of std::ios_base)

Internal extensible array
   xalloc returns a program-wide unique integer that is safe to use as index
   [static] to pword() and iword()
                     (public static member function of std::ios_base)
                     resizes the private storage if necessary and access to the long
   iword element at the given index
                     (public member function of std::ios_base)
                     resizes the private storage if necessary and access to the void*
   pword element at the given index
                     (public member function of std::ios_base)

Miscellaneous
   register_callback registers event callback function
                     (public member function of std::ios_base)
   sync_with_stdio sets whether C++ and C I/O libraries are interoperable
   [static] (public static member function of std::ios_base)

Member classes
   failure stream exception
                     (public member class of std::ios_base)
   Init initializes standard stream objects
                     (public member class of std::ios_base)

Member types and constants
   Type Explanation
                  stream open mode type
                  The following constants are also defined:
                  Constant Explanation
                  app seek to the end of stream before each write
                  binary open in binary mode
   openmode in open for reading
                  out open for writing
                  trunc discard the contents of the stream when
                        opening
                  ate seek to the end of stream immediately after
                        open
                  noreplace (C++23) open in exclusive mode
                  (typedef)
                  formatting flags type
                  The following constants are also defined:
                  Constant Explanation
                  dec use decimal base for integer I/O: see std::dec
                  oct use octal base for integer I/O: see std::oct
                  hex use hexadecimal base for integer I/O: see std::hex
                  basefield dec | oct | hex. Useful for masking operations
                  left left adjustment (adds fill characters to the right): see
                        std::left
                  right right adjustment (adds fill characters to the left): see
                        std::right
                  internal internal adjustment (adds fill characters to the internal
                        designated point): see std::internal
                  adjustfield left | right | internal. Useful for masking
                        operations
                        generate floating point types using scientific notation,
                  scientific or hex notation if combined with fixed: see
                        std::scientific
   fmtflags generate floating point types using fixed notation, or
                  fixed hex notation if combined with scientific: see
                        std::fixed
                  floatfield scientific | fixed. Useful for masking operations
                  boolalpha insert and extract bool type in alphanumeric format: see
                        std::boolalpha
                        generate a prefix indicating the numeric base for integer
                  showbase output, require the currency indicator in monetary I/O:
                        see std::showbase
                  showpoint generate a decimal-point character unconditionally for
                        floating-point number output: see std::showpoint
                  showpos generate a + character for non-negative numeric output:
                        see std::showpos
                  skipws skip leading whitespace before certain input operations:
                        see std::skipws
                  unitbuf flush the output after each output operation: see
                        std::unitbuf
                        replace certain lowercase letters with their uppercase
                  uppercase equivalents in certain output operations: see
                        std::uppercase
                  (typedef)
                  state of the stream type
                  The following constants are also defined:
                  Constant Explanation
   iostate goodbit no error
                  badbit irrecoverable stream error
                  failbit input/output operation failed (formatting or extraction
                        error)
                  eofbit associated input sequence has reached end-of-file
                  (typedef)
                  seeking direction type
                  The following constants are also defined:
   seekdir Constant Explanation
                  beg the beginning of a stream
                  end the ending of a stream
                  cur the current position of stream position indicator
                  (typedef)
   event specifies event type
                  (enum)
   event_callback callback function type
                  (typedef)
   Defect reports
   The following behavior-changing defect reports were applied retroactively to
   previously published C++ standards.
     DR Applied to Behavior as published Correct behavior
                      the member types char_type, traits_type,
   LWG 271 C++98 int_type, pos_type and off_type were not defined define
                      (std::basic_istream and std::basic_ostream both these types
                      define these types, resulted in ambiguity)

See also
     * Input/output manipulators