std::basic_filebuf
From cppreference.com
| Defined in header <fstream>
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| template< class CharT, |
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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> |
Member types
| Member type | Definition |
char_type
|
CharT |
traits_type
|
Traits |
int_type
|
Traits::int_type |
pos_type
|
Traits::pos_type which is required to be std::fpos<Traits::state_type> |
off_type
|
Traits::off_type |
Member functions
Public member functions | |
| constructs a basic_filebuf object (public member function) | |
| (C++11) |
assigns a basic_filebuf object (public member function) |
| (C++11) |
swaps two basic_filebuf objects (public member function) |
| [virtual] |
destructs a basic_filebuf object and closes the file if it is open (virtual public member function) |
| checks if the associated file is open (public member function) | |
| opens a file and configures it as the associated character sequence (public member function) | |
| flushes the put area buffer and closes the associated file (public member function) | |
Protected member functions | |
| [virtual] |
optionally provides the number of characters available for input from the file (virtual protected member function) |
| [virtual] |
reads from the associated file (virtual protected member function) |
| [virtual] |
reads from the associated file and advances the next pointer in the get area (virtual protected member function) |
| [virtual] |
backs out the input sequence to unget a character, not affecting the associated file (virtual protected member function) |
| [virtual] |
writes characters to the associated file from the put area (virtual protected member function) |
| [virtual] |
provides user-supplied buffer or turns this filebuf unbuffered (virtual protected member function) |
| [virtual] |
repositions the file position, using relative addressing (virtual protected member function) |
| [virtual] |
repositions the file position, using absolute addressing (virtual protected member function) |
| [virtual] |
writes characters to the associated file from the put area (virtual protected member function) |
| [virtual] |
changes the associated locale (virtual protected member function) |
Non-member functions
| specializes the std::swap algorithm (function template) |
Inherited from std::basic_streambuf
Member types
| Member type | Definition |
char_type
|
CharT |
traits_type
|
Traits |
int_type
|
Traits::int_type |
pos_type
|
Traits::pos_type |
off_type
|
Traits::off_type |
Member functions
| [virtual] |
destructs the basic_streambuf object (virtual public member function of std::basic_streambuf) |
Locales | |
| invokes imbue() (public member function of std::basic_streambuf) | |
| obtains a copy of the associated locale (public member function of std::basic_streambuf) | |
Positioning | |
| invokes setbuf() (public member function of std::basic_streambuf) | |
| invokes seekoff() (public member function of std::basic_streambuf) | |
| invokes seekpos() (public member function of std::basic_streambuf) | |
| invokes sync() (public member function of std::basic_streambuf) | |
Get area | |
| obtains the number of characters immediately available in the get area (public member function of std::basic_streambuf) | |
| advances the input sequence, then reads one character without advancing again (public member function of std::basic_streambuf) | |
| reads one character from the input sequence and advances the sequence (public member function of std::basic_streambuf) | |
| stossc (deprecated) (until C++17) |
advances the input sequence as if by calling sbumpc() and discarding the result (public member function) |
| reads one character from the input sequence without advancing the sequence (public member function of std::basic_streambuf) | |
| invokes xsgetn() (public member function of std::basic_streambuf) | |
Put area | |
| writes one character to the put area and advances the next pointer (public member function of std::basic_streambuf) | |
| invokes xsputn() (public member function of std::basic_streambuf) | |
Putback | |
| puts one character back in the input sequence (public member function of std::basic_streambuf) | |
| moves the next pointer in the input sequence back by one (public member function of std::basic_streambuf) | |
Protected member functions
| constructs a basic_streambuf object (protected member function) | |
| (C++11) |
replaces a basic_streambuf object (protected member function) |
| (C++11) |
swaps two basic_streambuf objects (protected member function) |
Locales | |
| [virtual] |
changes the associated locale (virtual protected member function of std::basic_streambuf) |
Positioning | |
| [virtual] |
replaces the buffer with user-defined array, if permitted (virtual protected member function of std::basic_streambuf) |
| [virtual] |
repositions the next pointer in the input sequence, output sequence, or both, using relative addressing (virtual protected member function of std::basic_streambuf) |
| [virtual] |
repositions the next pointer in the input sequence, output sequence, or both using absolute addressing (virtual protected member function of std::basic_streambuf) |
| [virtual] |
synchronizes the buffers with the associated character sequence (virtual protected member function of std::basic_streambuf) |
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) |
| [virtual] |
reads characters from the associated input sequence to the get area (virtual protected member function of std::basic_streambuf) |
| [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) |
| [virtual] |
reads multiple characters from the input sequence (virtual protected member function of std::basic_streambuf) |
| returns a pointer to the beginning, current character and the end of the get area (protected member function) | |
| advances the next pointer in the input sequence (protected member function) | |
| repositions the beginning, next, and end pointers of the input sequence (protected member function) | |
Put area | |
| [virtual] |
writes multiple characters to the output sequence (virtual protected member function of std::basic_streambuf) |
| [virtual] |
writes characters to the associated output sequence from the put area (virtual protected member function of std::basic_streambuf) |
| returns a pointer to the beginning, current character and the end of the put area (protected member function) | |
| advances the next pointer of the output sequence (protected member function) | |
| repositions the beginning, next, and end pointers of the output sequence (protected member function) | |
Putback | |
| [virtual] |
puts a character back into the input sequence, possibly modifying the input sequence (virtual protected member function of std::basic_streambuf) |