关于使用一个长度为0的数组来实现变长结构体

BYTE* Next() {return (char *)m_pA + sizeof(int) + Len();}

class A

	{

	BYTE *m_pA;

public:

	A(BYTE *pA) : m_pA(pA) {}



	int Len() {return *(int *)m_pA;}

	char Buf(size_t n = 0) {return *((char *)m_pA + sizeof(int) + n);}

	};



int asdf(BYTE *pMem)

	{

	A aaa(pMem);

	int nLen = aaa.Len();

	char Buf0 = aaa.Buf();

	char Buf100 = aaa.Buf(100);

	};

struct A

    {

    int nLen;

    char pBuf[1];

    };

size_t nMaxAlign = sizeof(结构体中对齐要求最严格的类型);

size_t nVarAlign = sizeof(变长数组元素类型);

size_t nBufSize = sizeof(A) - nMaxAlign + (nVarAlign * N + nMaxAlign - 1) / nMaxAlign * nMaxAlign;