[讨论] 对面的高手看过来，ST公司的数据结构啥意思

typedef union
{
  u16 whole;
  struct
  {
    unsigned IMPLEMENTED : 1; /**< Indicates that the key is implemented (from Customer Code to TSL only) */
    unsigned ENABLED     : 1; /**< Indicates that the key is enabled (from Customer Code to TSL only) */
    unsigned DETECTED    : 1; /**< Indicates that the key is detected (from TSL to Customer Code only) */
    unsigned CHANGED     : 1; /**< Indicates that the key state has changed (from TSL to Customer Code only) */
    unsigned POSCHANGED  : 1; /**< Indicates that the MC key position has changed (from TSL to Customer Code only) */
    unsigned ERROR       : 1; /**< Indicates that the key has an error (from TSL to Customer Code only) */
    unsigned NOISE       : 1; /**< Indicates that the key measurement has noise (from TSL to Customer Code only) */
    unsigned LOCKED      : 1; /**< Reserved (TSL internal usage) */
    unsigned DIRECTION   : 1; /**< Reserved (TSL internal usage) */
    unsigned MCKEY_TYPE  : 1; /**< Indicates the type of MCkey: Wheel(0) or Slider(1) (from Customer Code to TSL only) */
    unsigned RESERVED0   : 1; /**< Reserved for future use */
    unsigned RESERVED1   : 1; /**< Reserved for future use */
    unsigned RESERVED2   : 1; /**< Reserved for future use */
    unsigned RESERVED3   : 1; /**< Reserved for future use */
    unsigned RESERVED4   : 1; /**< Reserved for future use */
    unsigned RESERVED5   : 1; /**< Reserved for future use */
  } b;
} KeyFlag_T;
我不明白那个：号是做什么用地

定义结构体的时候，冒号后面跟数字代表占用的bit数。
这个实际上是定义了一个16bit的结构，里面每个bit的作用。