| Defined in header
<fstream> | ||
|---|---|---|
template<
class CharT,
class Traits = std::char_traits<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> |
| 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 |
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) |
| (C++11)
| specializes the std::swap algorithm (function template) |
| Member type | Definition |
|---|---|
char_type | CharT |
traits_type | Traits |
int_type | Traits::int_type |
pos_type | Traits::pos_type |
off_type | Traits::off_type |
| [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) |
|
| 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) |
© cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
http://en.cppreference.com/w/cpp/io/basic_filebuf