#include
#pragma pack(push,4)
struct MyStruct
{
unsigned char a;//
unsigned int b; //到这里是，加起来等于unsigned int 字节的倍数
unsigned char Cbuffer[10];//char没有字节对齐
unsigned int d;

};
#pragma pack()

void EnCodePack(unsigned char*cSendBuff,void *pSrc)
{
int pos =0;
MyStruct *ptr = (MyStruct *)(pSrc);
*(cSendBuff+pos) =ptr->a;
pos+=sizeof(ptr->a);
pos+=3;//字节偏差最大为1
((unsigned int)(cSendBuff+pos)) = ptr->b;
pos+=sizeof(ptr->b);
memcpy(cSendBuff+pos,ptr->Cbuffer,10);
pos+=sizeof(ptr->Cbuffer);
pos+=2;
((unsigned int)(cSendBuff+pos)) = ptr->d;
pos+=sizeof(ptr->d);
}

//然后所有的pos加起来就是字节对齐的倍数

int main()
{
unsigned char buffer[100] ={0};
MyStruct st;
int iDataSize = sizeof(st);
st.a =‘3’;
st.b =100;
memcpy(st.Cbuffer,“123456789”,10);
st.d =200;
EnCodePack(buffer,&st);
MyStructptr = (MyStruct)(buffer);
int xx =10;
}