std::basic_filebuf(3cxx) on Linux
The text 170bfaadc07c, as Debian 6.0 (Squeeze) shipped it.
The actual work of input and output (for files). This class associates both its input and output sequence with an external disk file, and maintains a joint file position for both sequences. Many of its semantics are described in terms of similar behavior in the Standard C Library's FILE streams.