Input/output library

Standard input/output library is organized in such a way that the underlying device of an input/output operation is abstracted. In this way the same code can handle input/output to a file, memory stream, or custom adaptor device interpreting the data on the fly, e.g. compressing it. Most of the classes are templated, so they can be adapted to any basic character type. Separate typedefs are provided for the most common basic character types (Template:cpp and Template:cpp).

Inheritance diagram

Abstraction
basic_streambuf	abstracts a raw device (class template)
basic_istream	wraps a given abstract device (Template:cpp) and provides high-level input interface (class template)
basic_ostream	wraps a given abstract device (Template:cpp) and provides high-level output interface (class template)
basic_iostream	wraps a given abstract device (Template:cpp) and provides high-level input/output interface (class template)
File I/0 implementation
basic_filebuf	implements raw file device (class template)
basic_ifstream	implements high-level file stream input operations (class template)
basic_ofstream	implements high-level file stream output operations (class template)
basic_fstream	implements high-level file stream input/output operations (class template)
String I/0 implementation
basic_stringbuf	implements raw string device (class template)
basic_istringstream	implements high-level string stream input operations (class template)
basic_ostringstream	implements high-level string stream output operations (class template)
basic_stringstream	implements high-level string stream input/output operations (class template)
Array I/O implementations
strstreambuf (deprecated)	implements raw character array device (class)
istrstream (deprecated)	implements character array input operations (class)
ostrstream (deprecated)	implements character array output operations (class)

Typedefs

The following typedefs for common character types are provided:

typedef basic_ios<char>                ios;
typedef basic_ios<wchar_t>            wios;
 
typedef basic_streambuf<char>     streambuf;
typedef basic_streambuf<wchar_t> wstreambuf;
typedef basic_filebuf<char>         filebuf;
typedef basic_filebuf<wchar_t>     wfilebuf;
typedef basic_stringbuf<char>     stringbuf;
typedef basic_stringbuf<wchar_t> wstringbuf;
 
typedef basic_istream<char>         istream;
typedef basic_istream<wchar_t>     wistream;
typedef basic_ostream<char>         ostream;
typedef basic_ostream<wchar_t>     wostream;
typedef basic_iostream<char>       iostream;
typedef basic_iostream<wchar_t>   wiostream;
 
typedef basic_ifstream<char>       ifstream;
typedef basic_ifstream<wchar_t>   wifstream;
typedef basic_ofstream<char>       ofstream;
typedef basic_ofstream<wchar_t>   wofstream;
typedef basic_fstream<char>         fstream;
typedef basic_fstream<wchar_t>     wfstream;
 
typedef basic_istringstream<char>     istringstream;
typedef basic_istringstream<wchar_t> wistringstream;
typedef basic_ostringstream<char>     ostringstream;
typedef basic_ostringstream<wchar_t> wostringstream;
typedef basic_stringstream<char>       stringstream;
typedef basic_stringstream<wchar_t>   wstringstream;

Predefined standard stream objects:

extern  istream  cin;   //standard input (stdin)
extern wistream wcin;
extern  ostream  cout;  //standard output (stdout)
extern wostream wcout;
extern  ostream  cerr;  //standard error (stderr)
extern wostream wcerr;
extern  ostream  clog;  //standard log (stdlog)
extern wostream wclog;

Types

The following auxiliary type are defined:

Defined in header <ios>
fpos	represents a position in a stream (class template)
streampos	represents a position in a narrow character streams (class template specialization)
wstreampos	represents a position in wide character streams (class template specialization)
streamoff	represents offset from a streampos, sufficient to represent any file size (typedef)
streamsize	represents the number of characters transferred in an I/O operation or the size of an I/O buffer (typedef)

Manipulators

Several manipulators are defined to control the formatting of input/output operations on streams.

Defined in header <ios>
boolalphanoboolalpha	switches between textual and numeric representation of booleans (function)
showbasenoshowbase	controls whether prefix is used to indicate numeric base (function)
showpointnoshowpoint	controls whether decimal point is always included in floating-point representation (function)
snowposnoshowpos	controls whether the + sign used with non-negative numbers (function)
skipwsnoskipws	controls whether leading whitespace is skipped on input (function)
uppercasenouppercase	controls whether uppercase characters are used with some output formats (function)
unitbufnounitbuf	controls whether output is flushed after each operation (function)
internalleftright	sets the placement of fill characters (function)
dechexoct	changes the base used for integer I/O (function)
fixedscientifichexfloatdefaultfloat (C++11)(C++11)	changes formatting used for floating-point I/O (function)
Defined in header <istream>
ws	consumes whitespace (function template)
Defined in header <ostream>
ends	outputs '\0' (function template)
flush	flushes the output stream (function template)
endl	outputs '\n' and flushes the output stream (function template)
Defined in header <iomanip>
resetiosflags	clears the specified ios_base flags (function)
setiosflags	sets the specified ios_base flags (function)
setbase	change the base used for integer I/O (function)
setfill	change fill character (function)
setprecision	change floating-point precision (function)
setw	change the width of the next output (function)
get_money (C++11)	parses a monetary value (function template)
put_money (C++11)	formats and outputs a monetary value (function template)
get_time (C++11)	parses a date/time value of specified format (function template)
put_time (C++11)	formats and outputs a date/time value according to the specified format (function template)

Error category interface

Template:dcl list ptfun

Defined in header <ios>
io_errc (C++11)	the system error category enumeration of IO error codes (class)
iostream_category (C++11)	constructs an iostream error category (function)
make_error_code(std::io_errc) (C++11)	constructs an iostream error code (function)
make_error_condition(std::io_errc) (C++11)	constructs an iostream error_condition (function)