istream_withassign( streambuf* psb );
istream_withassign();
psb
A pointer to an existing object of a streambuf-derived class.
The first constructor creates a ready-to-use object of type istream_withassign, complete with attached streambuf object.
The second constructor creates an object but does not initialize it. You must subsequently use the second variation of the istream_withassign assignment operator to attach the streambuf object, or you must use the first variation to initialize this object to match the specified istream object.
istream_withassign::operator =