protected member function void init (streambuf* sb); Initializes
the values of the stream's internal flags and member variables.
Derived classes are expected to call this protected member
function at some point before its first use or before its
destruction (generally, during construction). The internal state
is initialized in such a way that each of these members return
the following values: On initialization, the internal extensible
array (iword, pword) is empty. Modifies the stream object. The
object pointed by sb may be accessed and/or modified. Concurrent
access to the same stream object or stream buffer may cause data
races. Basic guarantee: if an exception is thrown, the stream is
in a valid state. - Construct object (public member function