That being said, the programmer almost never works directly with the stream buffer. These classes are isockstream, osockstream, and iosockstream. These last 3 classes are very simple. As shown below, isockstream defines only a few simple member functions. All of the work functions are inherited from ios and istream.
Internet sockets use the buffer class sockinetbuf.
The classes isockinet, osockinet and iosockinet are derived from their generic socket counter-parts. The sockbuf class performs all socket operations, binding, connecting, listening, etc. When a stream needs to write data, it calls member functions in the streambuf class to write the data into the buffer. The get and put areas are sections of the reserve area. O. Both underflow and overflow are virtual member functions of streambuf.