std::basic_ios(3)

NAME
std::basic_ios - std::basic_ios

Synopsis
   Defined in header <ios>
   template<
       class CharT,
       class Traits = std::char_traits<CharT>
   > class basic_ios
       : public std::ios_base
   The class std::basic_ios provides facilities for interfacing with objects that have
   std::basic_streambuf interface. Several std::basic_ios objects can refer to one
   actual std::basic_streambuf object.
   std-basic ios-inheritance.svg
                        Inheritance diagram
   Several typedefs for common character types are provided:
   Defined in header <ios>
   Type Definition
   std::ios std::basic_ios<char>
   std::wios std::basic_ios<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

Public member functions
   constructor constructs the object
                 (public member function)
   destructor destructs the object
   [virtual] (virtual public member function)
   operator= the copy assignment operator is deleted
                 (public member function)

State functions
   good checks if no error has occurred i.e. I/O operations are available
                 (public member function)
   eof checks if end-of-file has been reached
                 (public member function)
   fail checks if an error has occurred
                 (public member function)
   bad checks if a non-recoverable error has occurred
                 (public member function)
   operator! checks if an error has occurred (synonym of fail())
                 (public member function)
   operator bool checks if no error has occurred (synonym of !fail())
                 (public member function)
   rdstate returns state flags
                 (public member function)
   setstate sets state flags
                 (public member function)
   clear modifies state flags
                 (public member function)

Formatting
   copyfmt copies formatting information
                 (public member function)
   fill manages the fill character
                 (public member function)

Miscellaneous
   exceptions manages exception mask
                 (public member function)
   imbue sets the locale
                 (public member function)
   rdbuf manages associated stream buffer
                 (public member function)
   tie manages tied stream
                 (public member function)
   narrow narrows characters
                 (public member function)
   widen widens characters
                 (public member function)

Protected member functions
   init initializes a default-constructed std::basic_ios
             (protected member function)
   move moves from another std::basic_ios except for rdbuf
   (C++11) (protected member function)
   swap swaps with another std::basic_ios except for rdbuf
   (C++11) (protected member function)
   set_rdbuf replaces the rdbuf without clearing its error state
             (protected member function) 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)

Notes
   Straightforward implementation of std::basic_ios stores only the following members
   (which all depend on the template parameters and thus cannot be part of
   std::ios_base):
     * the fill character (see fill())
     * the tied stream pointer (see tie())
     * the associated stream buffer pointer (see rdbuf()).
   Actual implementations vary:
   Microsoft Visual Studio stores just those three members.
   LLVM libc++ stores 1 less member: it maintains the rdbuf pointer as a void* member
   of ios_base.
   GNU libstdc++ stores 4 additional members: three cached facets and a flag to
   indicate that fill was initialized.