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File stream buffer
Class hierarchy:
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filebuf |
This class applies the functionality of the streambuf class to read and write from/to files.
By calling member open, a physical file is associated to the file buffer as its associated character sequence. Depending on the mode used in this operation, the access to the controlled input sequence or the controlled output sequence may be restricted.
The state of the filebuf object -i.e. wether a file is open or not- may be tested by calling member function is_open.
Internally, filebuf objects operate as defined in the streambuf class (see streambuf), with the particularity that a joint position pointer is maintained for both the input and the output controlled sequences.
The class overrides some virtual members inherited from streambuf to provide a specific functionality for files.
Public members
| (constructor) | Construct a file stream buffer object (constructor member) |
| is_open | Check if a file is open (public member function) |
| open | Open file (public member function) |
| close | Close file (public member function) |
Public members inherited from streambuf:
| getloc | Get current locale (public member function) |
| in_avail | Get number of characters available to read (public member function) |
| pubimbue | Imbue locale (public member function) |
| pubseekoff | Set internal position pointer to relative position (public member function) |
| pubseekpos | Set internal position pointer to absolute position (public member function) |
| pubsetbuf | Set buffer array (public member function) |
| pubsync | Synchronize stream buffer (public member function) |
| sbumpc | Get current character and increase get pointer (public member function) |
| sgetc | Get current character (public member function) |
| sgetn | Get sequence of characters (public member function) |
| snextc | Increase get pointer and return next character (public member function) |
| sputbackc | Put character back (public member function) |
| sputc | Store character at current put position and increase put pointer (public member function) |
| sputn | Write a sequence of characters (public member function) |
Virtual protected members
The parent class streambuf defines several protected virtual functions that are called by the other member functions to perform the operations on the associated character sequence. Derived classes override these virtual member functions as necessary to provide the functionality for their specific types of buffer. filebuf overrides the following:
| showmanyc | Get number of characters available in the sequence (virtual protected member function) |
| underflow | Get character in the case of underflow (virtual protected member function) |
| uflow | Get character in the case of underflow and advance get pointer (virtual protected member function) |
| pbackfail | Put character back on backup underflow (virtual protected member) |
| overflow | Write character (virtual protected member function) |
| setbuf | Set buffer (virtual protected member function) |
| seekoff | Set internal position pointer to relative position (virtual protected member function) |
| seekpos | Set internal position pointer to absolute position (virtual protected member function) |
| sync | Synchronize file buffer (virtual protected member function) |
| imbue | Imbue locale (virtual protected member function) |
The remaining virtual protectected members (xsgetn and xsputn) are left with their by-default behavior defined in streambuf.
Protected members
The class also inherits several non-virtual protected members used by the public functions to access the internal pointers. See streambuf for more info.
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