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 (char and wchar_t).

Inheritance diagram

Abstraction
ios_base	manages formatting flags and input/output exceptions (class)
basic_ios	manages an arbitrary stream buffer (class template)
basic_streambuf	abstracts a raw device (class template)
basic_istream	wraps a given abstract device (std::basic_streambuf) and provides high-level input interface (class template)
basic_ostream	wraps a given abstract device (std::basic_streambuf) and provides high-level output interface (class template)
basic_iostream	wraps a given abstract device (std::basic_streambuf) 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)
strstream (deprecated)	implements character array input/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>
streamoff	represents relative file/stream position (offset from fpos), 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)
fpos	represents absolute position in a stream or a file (class template)

Four specializations of std::fpos are provided: Template:tdcl list begin Template:tdcl list header Template:tdcl list hitem Template:tdcl list item Template:tdcl list item Template:tdcl list item Template:tdcl list item Template:tdcl list end

Error category interface

Template:cpp/io/dcl list io errcTemplate:cpp/io/dcl list iostream category

Defined in header <ios>