std::ostream (3) - Linux Manuals

std::ostream: std::basic_ostream

NAME

std::basic_ostream - std::basic_ostream

Synopsis

Defined in header <ostream>
template<
class CharT,
class Traits = std::char_traits<CharT>
> class basic_ostream : virtual public std::basic_ios<CharT, Traits>

The class template basic_ostream provides support for high level output operations on character streams. The supported operations include formatted output (e.g. integer values) and unformatted output (e.g. raw characters and character arrays). This functionality is implemented in terms of the interface provided by the basic_streambuf class, accessed through the basic_ios base class. In typical implementations, basic_ostream has no non-inherited data members.
 std-basic ostream-inheritance.svg
Inheritance diagram
Two specializations for common character types are also defined:

Defined in header <ostream>
Type Definition
ostream basic_ostream<char>
wostream basic_ostream<wchar_t>

Global objects

Six global basic_ostream objects are provided by the standard library.

Defined in header <iostream>
      writes to the standard C output stream stdout
cout (global object)
wcout
      writes to the standard C error stream stderr, unbuffered
cerr (global object)
wcerr
      writes to the standard C error stream stderr
clog (global object)
wclog

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

              constructs the object
constructor (public member function)

destructor destructs the object
              (virtual public member function)
[virtual]

operator= move-assigns from another basic_ostream
              (protected member function)
(C++11)

Formatted output

              inserts formatted data
operator<< (public member function)

Unformatted output

              inserts a character
put (public member function)
              inserts blocks of characters
write (public member function)

Positioning

              returns the output position indicator
tellp (public member function)
              sets the output position indicator
seekp (public member function)

Miscellaneous

              synchronizes with the underlying storage device
flush (public member function)

swap swaps stream objects, except for the associated buffer
              (protected member function)
(C++11)

Member classes

       implements basic logic for preparation of the stream for output operations
sentry (public member class)

Non-member functions

                               inserts character data
operator<<(std::basic_ostream) (function template)

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

               checks if no error has occurred i.e. I/O operations are available
good (public member function of std::basic_ios<CharT,Traits>)
               checks if end-of-file has been reached
eof (public member function of std::basic_ios<CharT,Traits>)
               checks if an error has occurred
fail (public member function of std::basic_ios<CharT,Traits>)
               checks if a non-recoverable error has occurred
bad (public member function of std::basic_ios<CharT,Traits>)
               checks if an error has occurred (synonym of fail())
operator! (public member function of std::basic_ios<CharT,Traits>)

operator_void*
operator_bool checks if no error has occurred (synonym of !fail())
               (public member function of std::basic_ios<CharT,Traits>)
(until C++11)
(since C++11)
               returns state flags
rdstate (public member function of std::basic_ios<CharT,Traits>)
               sets state flags
setstate (public member function of std::basic_ios<CharT,Traits>)
               modifies state flags
clear (public member function of std::basic_ios<CharT,Traits>)

Formatting

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

Miscellaneous

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

Inherited from std::ios_base

Member functions

Formatting

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

Locales

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

Internal extensible array

xalloc 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)
[static]
                  resizes the private storage if necessary and access to the long element at the given index
iword (public member function of std::ios_base)
                  resizes the private storage if necessary and access to the void* element at the given index
pword (public member function of std::ios_base)

Miscellaneous

                  registers event callback function
register_callback (public member function of std::ios_base)

sync_with_stdio sets whether C++ and C IO libraries are interoperable
                  (public static member function of std::ios_base)
[static]

Member classes

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

               (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
               scientific generate floating point types using scientific notation, 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 operations
               boolalpha insert and extract bool type in alphanumeric format: see std::boolalpha
               showbase generate a prefix indicating the numeric base for integer 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
               uppercase replace certain lowercase letters with their uppercase
                           equivalents in certain output operations: see std::uppercase

               (typedef)
               state of the stream type
               The following constants are also defined:

               Constant Explanation
               goodbit no error
iostate 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:

               Constant Explanation
               beg the beginning of a stream
seekdir end the ending of a stream
               cur the current position of stream position indicator

               (typedef)
               specifies event type
event (enum)
               callback function type
event_callback (typedef)