std::basic_filebuf
Defined in header <fstream> | ||
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template<
class CharT,
class Traits = std::char_traits<CharT>
> class basic_filebuf : public std::basic_streambuf<CharT, Traits>
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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> |
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|---|---|
| Type | Definition |
filebuf | basic_filebuf<char> |
wfilebuf | basic_filebuf<wchar_t> |
Member types
| Member type | Definition |
|---|---|
char_type | CharT
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traits_type | Traits; the program is ill-formed if Traits::char_type is not CharT. |
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
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Member functions
Public member functions |
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| constructs a basic_filebuf object (public member function) |
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(C++11) | assigns a basic_filebuf object (public member function) |
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(C++11) | swaps two basic_filebuf objects (public member function) |
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[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) |
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| opens a file and configures it as the associated character sequence (public member function) |
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| flushes the put area buffer and closes the associated file (public member function) |
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Protected member functions |
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[virtual] | optionally provides the number of characters available for input from the file (virtual protected member function) |
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[virtual] | reads from the associated file (virtual protected member function) |
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[virtual] | reads from the associated file and advances the next pointer in the get area (virtual protected member function) |
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[virtual] | backs out the input sequence to unget a character, not affecting the associated file (virtual protected member function) |
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[virtual] | writes characters to the associated file from the put area (virtual protected member function) |
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[virtual] | provides user-supplied buffer or turns this filebuf unbuffered (virtual protected member function) |
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[virtual] | repositions the file position, using relative addressing (virtual protected member function) |
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[virtual] | repositions the file position, using absolute addressing (virtual protected member function) |
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[virtual] | writes characters to the associated file from the put area (virtual protected member function) |
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[virtual] | changes the associated locale (virtual protected member function) |
Non-member functions
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(C++11) | specializes the std::swap algorithm (function template) |
Inherited from std::basic_streambuf
Member types
| Member type | Definition |
|---|---|
char_type | CharT
|
traits_type | Traits; the program is ill-formed if Traits::char_type is not CharT. |
int_type | Traits::int_type
|
pos_type | Traits::pos_type
|
off_type | Traits::off_type
|
Member functions
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[virtual] | destructs the basic_streambuf object (virtual public member function of std::basic_streambuf<CharT,Traits>) |
Locales |
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invokes imbue() (public member function of std::basic_streambuf<CharT,Traits>) |
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| obtains a copy of the associated locale (public member function of std::basic_streambuf<CharT,Traits>) |
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Positioning |
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invokes setbuf() (public member function of std::basic_streambuf<CharT,Traits>) |
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invokes seekoff() (public member function of std::basic_streambuf<CharT,Traits>) |
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invokes seekpos() (public member function of std::basic_streambuf<CharT,Traits>) |
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invokes sync() (public member function of std::basic_streambuf<CharT,Traits>) |
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Get area |
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| obtains the number of characters immediately available in the get area (public member function of std::basic_streambuf<CharT,Traits>) |
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| advances the input sequence, then reads one character without advancing again (public member function of std::basic_streambuf<CharT,Traits>) |
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| reads one character from the input sequence and advances the sequence (public member function of std::basic_streambuf<CharT,Traits>) |
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| stossc
(deprecated in C++98)(removed in 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<CharT,Traits>) |
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invokes xsgetn() (public member function of std::basic_streambuf<CharT,Traits>) |
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Put area |
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| writes one character to the put area and advances the next pointer (public member function of std::basic_streambuf<CharT,Traits>) |
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invokes xsputn() (public member function of std::basic_streambuf<CharT,Traits>) |
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Putback |
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| puts one character back in the input sequence (public member function of std::basic_streambuf<CharT,Traits>) |
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| moves the next pointer in the input sequence back by one (public member function of std::basic_streambuf<CharT,Traits>) |
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Protected member functions
| constructs a basic_streambuf object (protected member function) |
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(C++11) | replaces a basic_streambuf object (protected member function) |
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(C++11) | swaps two basic_streambuf objects (protected member function) |
Locales |
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[virtual] | changes the associated locale (virtual protected member function of std::basic_streambuf<CharT,Traits>) |
Positioning |
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[virtual] | replaces the buffer with user-defined array, if permitted (virtual protected member function of std::basic_streambuf<CharT,Traits>) |
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[virtual] | repositions the next pointer in the input sequence, output sequence, or both, using relative addressing (virtual protected member function of std::basic_streambuf<CharT,Traits>) |
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[virtual] | repositions the next pointer in the input sequence, output sequence, or both using absolute addressing (virtual protected member function of std::basic_streambuf<CharT,Traits>) |
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[virtual] | synchronizes the buffers with the associated character sequence (virtual protected member function of std::basic_streambuf<CharT,Traits>) |
Get area |
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[virtual] | obtains the number of characters available for input in the associated input sequence, if known (virtual protected member function of std::basic_streambuf<CharT,Traits>) |
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[virtual] | reads characters from the associated input sequence to the get area (virtual protected member function of std::basic_streambuf<CharT,Traits>) |
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[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<CharT,Traits>) |
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[virtual] | reads multiple characters from the input sequence (virtual protected member function of std::basic_streambuf<CharT,Traits>) |
| returns a pointer to the beginning, current character and the end of the get area (protected member function) |
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| advances the next pointer in the input sequence (protected member function) |
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| repositions the beginning, next, and end pointers of the input sequence (protected member function) |
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Put area |
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[virtual] | writes multiple characters to the output sequence (virtual protected member function of std::basic_streambuf<CharT,Traits>) |
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[virtual] | writes characters to the associated output sequence from the put area (virtual protected member function of std::basic_streambuf<CharT,Traits>) |
| returns a pointer to the beginning, current character and the end of the put area (protected member function) |
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| advances the next pointer of the output sequence (protected member function) |
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| repositions the beginning, next, and end pointers of the output sequence (protected member function) |
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Putback |
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[virtual] | puts a character back into the input sequence, possibly modifying the input sequence (virtual protected member function of std::basic_streambuf<CharT,Traits>) |
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