无法访问工会内的匿名结构成员

Question

我在工作中使用联合和匿名结构。我想知道如何访问它内部的结构成员。就像如果我想使用union变量访问结构的G变量那么我该怎么做。请帮助:)

typedef union 
{ 
uint8_t All;     
struct 
{ 
    uint8_t G:1;    
    uint8_t O_B:1;   
    uint8_t Unused:1;  
    uint8_t W1:1;   
    uint8_t W2:1;   
    uint8_t Y1:1;   
    uint8_t Y2:1;   
    uint8_t IAQ:1;   
}; 
} _UNION_VARIABLE; 

我收到编译错误的访问结构成员象下面这样：

_UNION_VARIABLE sg_RefreshVar; 

sg_RefreshVar.G = false; 

错误： #137 union "<unnamed>" has no field "G"

Answer 1

你需要给它一个名称

typedef union 
{ 
uint8_t All;     
struct 
{ 
    uint8_t G:1;    
    uint8_t O_B:1;   
    uint8_t Unused:1;  
    uint8_t W1:1;   
    uint8_t W2:1;   
    uint8_t Y1:1;   
    uint8_t Y2:1;   
    uint8_t IAQ:1;   
} bit_field; 
} _UNION_VARIABLE; 

然后你可以去

_UNION_VARIABLE.bit_field.G;