关于c的一段程序，看不太明白！请高手指点！

只看该作者 · 2008-11-22 18:58

尤其是那个 near 弄得我比较糊涂

程序如下：
union
{
    struct
    {
        unsigned B0:1;
        unsigned B1:1;
        unsigned B2:1;
        unsigned B3:1;
        unsigned B4:1;
        unsigned B5:1;
        unsigned B6:1;
        unsigned B7:1;
    };
    unsigned char nLedValue;
}near nLedValue2U,nLedValue3U,nLedValue4U,nLedValue5U,nLedValue6U,
nLedValue7U,nLedValue8U,nLedValue9U,nLedValue10U,nLedValue11U;

#define nLedValue2     nLedValue2U.nLedValue
#define nLedValue3     nLedValue3U.nLedValue
#define nLedValue4     nLedValue4U.nLedValue
#define nLedValue5     nLedValue5U.nLedValue
#define nLedValue6     nLedValue6U.nLedValue
#define nLedValue7     nLedValue7U.nLedValue
#define nLedValue8     nLedValue8U.nLedValue
#define nLedValue9     nLedValue9U.nLedValue
#define nLedValue10         nLedValue10U.nLedValue
#define nLedValue11         nLedValue11U.nLedValue

#define bLedLine4        nLedValue2U.B0
#define bLedLine3        nLedValue2U.B1
#define bLedLine2        nLedValue2U.B2
#define bLedLine1        nLedValue2U.B3
#define bLedReturn      nLedValue2U.B4
#define bLedReturnDp1     nLedValue2U.B5
#define bLedReturnDp2    nLedValue2U.B6
#define bLedReturnDp3    nLedValue2U.B7

#define bLedBackAuto    nLedValue3U.B0
#define bLedBackCustom    nLedValue3U.B1
#define bLedKnead        nLedValue3U.B2
#define bLedKnock        nLedValue3U.B3
#define bLedSync        nLedValue3U.B4
#define bLedKneadB        nLedValue3U.B5
#define bLedPress        nLedValue3U.B6
#define bLedTap        nLedValue3U.B7