c++ io manipulator

std::cout << std::setw(8) << std::setfill('0') 

_MRTIMP2 _Smanip<streamsize> __cdecl setw(streamsize wide)
	{	// manipulator to set width
	return (_Smanip<streamsize>(&swfun, wide));
	}

		// FUNCTION setw
static void __cdecl swfun(ios_base& iostr, streamsize wide)
	{	// set width
	iostr.width(wide);
	}

		// TEMPLATE STRUCT _Smanip
template<class _Arg>
	struct _Smanip
	{	// store function pointer and argument value
	_Smanip(void (__cdecl *_Left)(ios_base&, _Arg), _Arg _Val)
		: _Pfun(_Left), _Manarg(_Val)
		{	// construct from function pointer and argument value
		}

	void (__cdecl *_Pfun)(ios_base&, _Arg);	// the function pointer
	_Arg _Manarg;	// the argument value
	};

template<class _Elem,
	class _Traits,
	class _Arg> inline
	basic_ostream<_Elem, _Traits>& operator<<(
		basic_ostream<_Elem, _Traits>& _Ostr, const _Smanip<_Arg>& _Manip)
	{	// insert by calling function with output stream and argument
	(*_Manip._Pfun)(_Ostr, _Manip._Manarg);
	return (_Ostr);
	}