自定数据结构强制转换为unsigned char类型？解决思路

自定数据结构强制转换为unsigned char类型？
我写了个类型

struct can_header{ //can frame head
canid_t id:11;
canid_t rtr:1;
canid_t ide:1;
canid_t dlc:4;
canid_t eid:18;
};

struct can_frame{
  struct can_header header;  
  unsigned char data[8]; 
};

希望通过write传给kernel。

struct can_frame *canframe;
canframe=(struct can_frame *) malloc(sizeof(struct can_frame));
memset(canframe,0,sizeof(struct can_frame));

write(fd,(unsigned char *) canframe, sizeof(struct can_frame));
但是没传进去，于是改了

unsigned char str[8] = {0x31,0x32,0x33,0x34,0x35,0x36,0x37,0x38};
write(fd,str,24);传进去了

kernel中函数是static int mcp251x_write(struct file *file, const char *buf, size_t count, loff_t *ofs)

请问我把canframe指针类型自定义结构强制转换为unsigned char指针类型，用(unsigned char *) canframe为什么不行？谢谢高手指

点。


[解决办法]
这个需要调试了。很可能两个所谓的“write”函数并不相同。