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std::basic_filebuf

From cppreference.com
< cpp‎ | io
Defined in header <fstream>
template<

    class charT,
    class Traits = std::char_traits<CharT>,
    class Allocator = std::allocator<CharT>

> class basic_filebuf : public std::basic_streambuf<CharT, Traits>

std::basic_filebuf is a std::basic_streambuf whose associated character sequence is a file. Both the input sequence and the output sequence are associated with the same file, and a joint file position is maintained for both operations.

The functions underflow() and overflow()/sync() perform the actual I/O between the file and the get and put areas of the buffer. When CharT is not char, most implementations store multibyte characters in the file and a std::codecvt facet is used to perform wide/multibyte character conversion.

Two specializations for common character types are also defined:

Defined in header <streambuf>
Type Definition
filebuf basic_filebuf<char>
wfilebuf basic_filebuf<wchar_t>

Contents

[edit] Member types

Member type Definition
char_type CharT[edit]
traits_type Traits[edit]
int_type Traits::int_type[edit]
pos_type Traits::pos_type which is required to be std::fpos<Traits::state_type>
off_type Traits::off_type[edit]

[edit] Member functions

Public member functions

constructs a basic_filebuf object
(public member function) [edit]
(C++11)
assigns a basic_filebuf object
(public member function) [edit]
(C++11)
swaps two basic_filebuf objects
(public member function) [edit]
[virtual]
destructs a basic_filebuf object and closes the file if it is open
(virtual public member function) [edit]
checks if the associated file is open
(public member function) [edit]
opens a file and configures it as the associated character sequence
(public member function) [edit]
flushes the put area buffer and closes the associated file
(public member function) [edit]

Protected member functions

[virtual]
optionally provides the number of characters available for input from the file
(virtual protected member function) [edit]
[virtual]
reads from the associated file
(virtual protected member function) [edit]
[virtual]
reads from the associated file and advances the next pointer in the get area
(virtual protected member function) [edit]
[virtual]
backs out the input sequence to unget a character, not affecting the associated file
(virtual protected member function) [edit]
[virtual]
writes characters to the associated file from the put area
(virtual protected member function) [edit]
[virtual]
provides user-supplied buffer or turns this filebuf unbuffered
(virtual protected member function) [edit]
[virtual]
repositions the file position, using relative addressing
(virtual protected member function) [edit]
[virtual]
repositions the file position, using absolute addressing
(virtual protected member function) [edit]
[virtual]
writes characters to the associated file from the put area
(virtual protected member function) [edit]
[virtual]
changes the associated locale
(virtual protected member function) [edit]

[edit] Non-member functions

specializes the std::swap algorithm
(function template) [edit]

Inherited from std::basic_streambuf

Member types

Member type Definition
char_type CharT[edit]
traits_type Traits[edit]
int_type Traits::int_type[edit]
pos_type Traits::pos_type[edit]
off_type Traits::off_type[edit]

Member functions

[virtual]
destructs the basic_streambuf object
(virtual public member function of std::basic_streambuf) [edit]
Locales
invokes imbue()
(public member function of std::basic_streambuf) [edit]
obtains a copy of the associated locale
(public member function of std::basic_streambuf) [edit]
Positioning
invokes setbuf()
(public member function of std::basic_streambuf) [edit]
invokes seekoff()
(public member function of std::basic_streambuf) [edit]
invokes seekpos()
(public member function of std::basic_streambuf) [edit]
invokes sync()
(public member function of std::basic_streambuf) [edit]
Get area
obtains the number of characters immediately available in the get area
(public member function of std::basic_streambuf) [edit]
advances the input sequence, then reads one character without advancing again
(public member function of std::basic_streambuf) [edit]
reads one character from the input sequence and advances the sequence
(public member function of std::basic_streambuf) [edit]
stossc
(deprecated)
advances the input sequence as if by calling sbumpc() and discarding the result
(public member function) [edit]
reads one character from the input sequence without advancing the sequence
(public member function of std::basic_streambuf) [edit]
invokes xsgetn()
(public member function of std::basic_streambuf) [edit]
Put area
writes one character to the put area and advances the next pointer
(public member function of std::basic_streambuf) [edit]
invokes xsputn()
(public member function of std::basic_streambuf) [edit]
Putback
puts one character back in the input sequence
(public member function of std::basic_streambuf) [edit]
moves the next pointer in the input sequence back by one
(public member function of std::basic_streambuf) [edit]

Protected member functions

constructs a basic_streambuf object
(protected member function) [edit]
(C++11)
replaces a basic_streambuf object
(protected member function) [edit]
(C++11)
swaps two basic_streambuf objects
(protected member function) [edit]
Locales
[virtual]
changes the associated locale
(virtual protected member function of std::basic_streambuf) [edit]
Positioning
[virtual]
replaces the buffer with user-defined array, if permitted
(virtual protected member function of std::basic_streambuf) [edit]
[virtual]
repositions the next pointer in the input sequence, output sequence, or both, using relative addressing
(virtual protected member function of std::basic_streambuf) [edit]
[virtual]
repositions the next pointer in the input sequence, output sequence, or both using absolute addressing
(virtual protected member function of std::basic_streambuf) [edit]
[virtual]
synchronizes the buffers with the associated character sequence
(virtual protected member function of std::basic_streambuf) [edit]
Get area
[virtual]
obtains the number of characters available for input in the associated input sequence, if known
(virtual protected member function of std::basic_streambuf) [edit]
[virtual]
reads characters from the associated input sequence to the get area
(virtual protected member function of std::basic_streambuf) [edit]
[virtual]
reads characters from the associated input sequence to the get area and advances the next pointer
(virtual protected member function of std::basic_streambuf) [edit]
[virtual]
reads multiple characters from the input sequence
(virtual protected member function of std::basic_streambuf) [edit]
returns a pointer to the beginning, current character and the end of the get area
(protected member function) [edit]
advances the next pointer in the input sequence
(protected member function) [edit]
repositions the beginning, next, and end pointers of the input sequence
(protected member function) [edit]
Put area
[virtual]
writes multiple characters to the output sequence
(virtual protected member function of std::basic_streambuf) [edit]
[virtual]
writes characters to the associated output sequence from the put area
(virtual protected member function of std::basic_streambuf) [edit]
returns a pointer to the beginning, current character and the end of the put area
(protected member function) [edit]
advances the next pointer of the output sequence
(protected member function) [edit]
repositions the beginning, next, and end pointers of the output sequence
(protected member function) [edit]
Putback
[virtual]
puts a character back into the input sequence, possibly modifying the input sequence
(virtual protected member function of std::basic_streambuf) [edit]