很奇怪的小程序，求解啊啊啊

#include <iostream>

using namespace std;

typedef struct _GUID {
    unsigned long  Data1;
    unsigned short Data2;
    unsigned short Data3;
    unsigned char  Data4[ 8 ];
} GUID;


void InitGUID(char* strGUID,GUID &guid)
{
sscanf_s(strGUID,"{%08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x}",&guid.Data1,&guid.Data2,&guid.Data3,&guid.Data4[0]
,&guid.Data4[1],&guid.Data4[2],&guid.Data4[3]
,&guid.Data4[4],&guid.Data4[5],&guid.Data4[6]
,&guid.Data4[7] );
}


int main()
{
int iSize = sizeof(GUID);
char *pBuf = "{739157EF-3F4E-4323-9A78-38591267DC40}";
GUID guid;
InitGUID(pBuf,guid);
return 0;
}

return 0后为什么栈溢出

结构体改为
typedef struct _GUID {
unsigned long Data1;
unsigned short Data2;
unsigned short Data3;
unsigned char Data4[ 9 ];
} GUID;

或者
typedef struct _GUID {
unsigned long Data1;
unsigned short Data2;
unsigned short Data3;
unsigned char Data4[ 8 ];
int i;
} GUID;
都可正常运行，百思不得其解，求大神指教一二,感激不尽！ C C++
[解决办法]
越界了，%x对应的数据类型是int，你给的是char，另外sscanf_s参数数目也不对