From cppreference.com
protected:voidinit(std::basic_streambuf<CharT,Traits>*sb);Sets the associated stream buffer to sb and initializes the internal state.
The postconditions are as follows:
Element Value
sb
null pointer
goodbit if sb is not a null pointer, otherwise badbit
goodbit
skipws|dec
0
6
widen(' ')
a copy of the value returned by std::locale()This member function is protected: it is called by the constructors of the derived stream classes
and
once the associated stream buffer is known. Until this function is called, every member function (including the destructor) of the default-constructed
invokes undefined behavior. Note that basic_ios is a virtual base class, and therefore its constructor is not called by the constructors of those directly derived classes, which is why two-stage initialization is necessary.
Parameters
sb - stream buffer to associate to See also