结构体 填充字段 知道的

结构体 填充字段 知道的高手请进
C专家编程中，
结构体填充字段，
struct pid_tag{ 
  unsigned int inactive :1; 
  unsigned int :1; 
  unsigned int refcount : 6; 
  unsigned int :0; 
  short pid_id; 
  struct pid_tag *link; 
} 看不明白。
填充字段是否占内存空间？如果占，占多少？是否是后面填充的数值？？这里很模糊，望理解的高手解释的清楚点。谢谢

------解决方案--------------------
inactive占一位
------解决方案--------------------
unsigned int inactive :1;
unsigned int :1;
unsigned int refcount : 6;
unsigned int :0;
由于一共8<32,因此一共占用sizeof(int)
------解决方案--------------------
LZ看看这两篇吧，看完就懂了
http://apps.hi.baidu.com/share/detail/15820795
http://www.programfan.com/blog/article.asp?id=30210
------解决方案--------------------

探讨

引用:

unsigned int inactive :1;
unsigned int :1;
unsigned int refcount : 6;
unsigned int :0;
由于一共8<32,因此一共占用sizeof(int)

struct pid_tag{
unsigned int inactive :1;
……

------解决方案--------------------
字节对齐
------解决方案--------------------
如果不填充那24个bit，
即：struct pid_tag{
unsigned int inactive :1;
unsigned int :1;
unsigned int refcount : 6;
// unsigned int :0;
short pid_id;
struct pid_tag *link;
}
引用:

unsigned int inactive :1; 
unsigned int :1; 
unsigned int refcount : 6; 
unsigned int :0; 
由于一共8<32,因此一共占用sizeof(int)

struct pid_tag{
unsigned int inactive :1;
unsigned int :1;
unsigned int refcount : 6;
unsigned int :0;
short pid_id;
struct pid_tag *link;
}
我sizeof上面的，结果是8
你确定是8么？什么编译器？我在vs2008下测试是12，unsigned int :0;加不加应该没关系啊