#define _OFFLINE		0x0001
#define _UP				0x0002
#define _DOWN           0x0004
#define _DEL			0x0008

	// 所有 1+2+4+8 = 15
	DWORD dwAA = _OFFLINE | _UP | _DOWN | _DEL;
	DWORD dwBB = 0;
	DWORD dwCC = 0;
	
	// 15 - 8 = 7
	dwAA = dwAA & ~_DEL;

	// 比较 如果含有 _OFFLINE 则得值 _OFFLINE 否则 0
	dwBB = (dwAA & _OFFLINE);
	// 比较 如果含有 _DEL 则得值 _DEL 否则 0
	dwCC = (dwAA & _DEL);

	// 
	if (_OFFLINE == dwBB)
	{

	}

	// 
	if (_DEL == dwCC)
	{

	}