Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
std::basic_ios(3)	      C++ Standard Libary	     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

	  Two specializations for common character types are also provided:

	  Type Definition
	  ios  basic_ios<char>
	  wios 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 void*
	  operator bool	 checks	if no error has	occurred (synonym of !fail())
	  (until C++11)	 (public member	function)
	  (since C++11)
	  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	opera-
       tions
			    (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 ac-
       cess to the long
	  iword		    element at the given index
			    (public member function of std::ios_base)
			    resizes the	private	storage	if necessary  and  ac-
       cess 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 interop-
       erable
	  [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
	  openmode	 binary	  open in binary mode
			 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

			 (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	opera-
       tions
			 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 sci-
       entific notation,
			 scientific  or	hex notation if	combined  with	fixed:
       see
				     std::scientific
	  fmtflags	 fixed	     generate floating point types using fixed
       notation, or
				     hex notation if combined with scientific:
       see std::fixed
			 floatfield   scientific|fixed.	Useful for masking op-
       erations
			 boolalpha   insert and	extract	bool type in  alphanu-
       meric 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	uncon-
       ditionally 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	opera-
       tion: 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 in-
       dicator

			 (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

http://cppreference.com		  2022.07.31		     std::basic_ios(3)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=std::basic_ios&sektion=3&manpath=FreeBSD+Ports+15.0>

home | help