为什么CSocket接收INT数据会错误..在线等待...

[lzd]

客户端代码
struct OpenPoint
{
short Game_Function;
char UserName[20];
int mOpenPoint;
};

CSocket m_pSocket;
OpenPoint m_OpenPoint;

char* CharUserName="daf"
ZeroMemory(&m_OpenPoint,sizeof(OpenPoint));
m_OpenPoint.Game_Function=2;
strcpy(m_OpenPoint.UserName,CharUserName);
m_OpenPoint.UserName[strlen(CharUserName)]='\0';
m_OpenPoint.mOpenPoint=100;


int send = 0;
while(send<sizeof(OpenPoint))
{
int nCharSend=m_pSocket->Send((void*)(&m_OpenPoint+send),sizeof(OpenPoint)-send,0);
send+=nCharSend;
}


服务器代码

struct OpenPoint
{
char UserName[20];
int mOpenPoint;
};

CSocket m_pServerSocket;
OpenPoint m_OpenPoint;
short temp;
m_pServerSocket->Receive(&temp,sizeof(short),0);
switch(temp)
{

case 0:
{
break;
}

case 2:
{
ZeroMemory(&m_OpenPoint,sizeof(OpenPoint));
int receive = 0;
while(receive<sizeof(OpenPoint))
{
int nCharSend=m_pServerSocket->Receive((void*)(&m_OpenPoint+receive),sizeof(OpenPoint)-receive,0);
receive+=nCharSend;
}
}

为什么接收到的m_pServerSocket.mOpenPoint=6553600(本来应该是100)而m_pServerSocket.UserName则正常?

[han012]

这是一个关于使用CSocket传输struct数据类型的非常经典的错误.

错误原因在于结构(struct)中有数据对齐属性!
关于这一点可以用sizeof(OpenPoint)来确认, 返回值不是你期望的!
不同的机器对于对齐属性有不同的设置,所以不进行1byte对齐而在不同的机器间传递结构一定会有多余的填充数据扰乱传输结果...

关于控制结构(struct)对齐属性有多种方法,最简单的方法如下:

1)open menu "project\settings..."
2)select "C\C++" tab
3)select "Code generation" category
4)select "1 Byte" from "struct member alignment" list
5)rebuild all projects and run again.

[everandforever]

没见有什么错,你CASE 2,BREAK了没有?

[everandforever]

啊,对数据对齐.

[lzd]

太谢谢啦..高手..给分啦...
我的QQ:11091594
MSN:[e-mail]

[everandforever]

struct OpenPoint
{
short Game_Function; //和USERNAME前2字节共占4字节
char UserName[20]; //剩下18字节,占5个四字节
int mOpenPoint; //占一个4字节.
};
struct OpenPoint
{
char UserName[20]; //占5个四字节
int mOpenPoint; //占一个四字节
};

解决方法:short Game_Function改为int类型就 可以 了.