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Difference between revisions of "cpp/io"

From cppreference.com
< cpp
(→‎Manipulators: let's define the manipulators separately)
m (specializations of fpos do not get their own pages. Also raised manipulators link, they are more important.)
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extern wostream wclog;
 
extern wostream wclog;
 
</source>
 
</source>
 +
 +
===[[cpp/io/manip|I/O Manipulators]]===
  
 
===Types===
 
===Types===
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{{dcl list begin}}
 
{{dcl list begin}}
 
{{dcl list header | ios }}
 
{{dcl list header | ios }}
−
{{dcl list tclass | cpp/io/fpos | represents a position in a stream }}
 
−
{{dcl list ptclass | cpp/io/streampos | represents a position in a narrow character streams}}
 
−
{{dcl list ptclass | cpp/io/wstreampos | represents a position in wide character streams}}
 
 
{{dcl list typedef | cpp/io/streamoff | represents offset from a streampos, sufficient to represent any file size }}
 
{{dcl list typedef | cpp/io/streamoff | represents offset from a streampos, sufficient to represent any file size }}
 
{{dcl list typedef | cpp/io/streamsize | represents the number of characters transferred in an I/O operation or the size of an I/O buffer}}
 
{{dcl list typedef | cpp/io/streamsize | represents the number of characters transferred in an I/O operation or the size of an I/O buffer}}
 +
{{dcl list tclass | cpp/io/fpos | represents a position in a stream }}
 
{{dcl list end}}
 
{{dcl list end}}
  
−
===[[cpp/io/manip|Manipulators]]===
+
Two specializations of {{cpp|std::fpos}} are provided:
 +
{{tdcl list begin}}
 +
{{tdcl list header | ios}}
 +
{{tdcl list hitem | Type | Definition}}
 +
{{tdcl list item | {{tt|streampos}} | {{cpp|std::fpos<std::char_traits<char>::state_type>}}}}
 +
{{tdcl list item | {{tt|wstreampos}} | {{cpp|std::fpos<std::char_traits<wchar_t>::state_type>}}}}
 +
{{tdcl list end}}
  
 
===Error category interface===
 
===Error category interface===

Revision as of 11:40, 16 November 2011

Template:cpp/io/sidebar

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).

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Inheritance diagram

Contents

Abstraction
abstracts a raw device
(class template)
wraps a given abstract device (Template:cpp)
and provides high-level input interface
(class template)
wraps a given abstract device (Template:cpp)
and provides high-level output interface
(class template)
wraps a given abstract device (Template:cpp)
and provides high-level input/output interface
(class template)
File I/0 implementation
implements raw file device
(class template)
implements high-level file stream input operations
(class template)
implements high-level file stream output operations
(class template)
implements high-level file stream input/output operations
(class template)
String I/0 implementation
implements raw string device
(class template)
implements high-level string stream input operations
(class template)
implements high-level string stream output operations
(class template)
implements high-level string stream input/output operations
(class template)
Array I/O implementations
(deprecated)
 implements raw character array device
(class)
(deprecated)
 implements character array input operations
(class)
(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;

I/O Manipulators

Types

The following auxiliary type are defined:

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

Two specializations of Template:cpp 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 end

Error category interface

Template:dcl list ptfun
Defined in header <ios>
(C++11)
 the system error category enumeration of IO error codes
(class)
(C++11)
 constructs an iostream error category
(function)
(C++11)
 constructs an iostream error code
(function)
(C++11)
 constructs an iostream error_condition
(function)

C-style input/output

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