Difference between revisions of "cpp/io"
From cppreference.com
< cpp
m (specializations of fpos do not get their own pages. Also raised manipulators link, they are more important.) |
m (+c++11 streamposes) |
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{{dcl list begin}} | {{dcl list begin}} | ||
{{dcl list header | ios }} | {{dcl list header | ios }} | ||
| − | {{dcl list typedef | cpp/io/streamoff | represents offset from | + | {{dcl list typedef | cpp/io/streamoff | represents relative file/stream position (offset from fpos), 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 | + | {{dcl list tclass | cpp/io/fpos | represents absolute position in a stream or a file}} |
{{dcl list end}} | {{dcl list end}} | ||
| − | + | Four specializations of {{cpp|std::fpos}} are provided: | |
{{tdcl list begin}} | {{tdcl list begin}} | ||
{{tdcl list header | ios}} | {{tdcl list header | ios}} | ||
{{tdcl list hitem | Type | Definition}} | {{tdcl list hitem | Type | Definition}} | ||
{{tdcl list item | {{tt|streampos}} | {{cpp|std::fpos<std::char_traits<char>::state_type>}}}} | {{tdcl list item | {{tt|streampos}} | {{cpp|std::fpos<std::char_traits<char>::state_type>}}}} | ||
| + | {{tdcl list item | {{tt|u16streampos}} | {{cpp|std::fpos<std::char_traits<char16_t>::state_type>}}}} | ||
| + | {{tdcl list item | {{tt|u32streampos}} | {{cpp|std::fpos<std::char_traits<char32_t>::state_type>}}}} | ||
{{tdcl list item | {{tt|wstreampos}} | {{cpp|std::fpos<std::char_traits<wchar_t>::state_type>}}}} | {{tdcl list item | {{tt|wstreampos}} | {{cpp|std::fpos<std::char_traits<wchar_t>::state_type>}}}} | ||
{{tdcl list end}} | {{tdcl list end}} | ||
Revision as of 12:31, 16 November 2011
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
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 relative file/stream position (offset from fpos), 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 absolute position in a stream or a file (class template) | |
Four 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 item Template:tdcl list item Template:tdcl list end
Error category interface
| Defined in header
<ios> | |
| (C++11) |
the system error category enumeration of IO error codes (class) |
| (C++11) |
constructs an iostream error category (function) |
| constructs an iostream error code (function) | |
| constructs an iostream error_condition (function) | |
