C语言位域应用--一个字节存八个标志位

/* define.h */
typedef struct {
    
	unsigned char bit0			:1;	
	unsigned char bit1			:1;
	unsigned char bit2			:1;
	unsigned char bit3			:1;
	unsigned char bit4			:1;
	unsigned char bit5			:1;
	unsigned char bit6			:1;
	unsigned char bit7			:1;
}_STC_BIT;

#define DEF_BIT7(pdata) ((volatile _STC_BIT*)(pdata))->bit7
#define DEF_BIT6(pdata) ((volatile _STC_BIT*)(pdata))->bit6
#define DEF_BIT5(pdata) ((volatile _STC_BIT*)(pdata))->bit5
#define DEF_BIT4(pdata) ((volatile _STC_BIT*)(pdata))->bit4
#define DEF_BIT3(pdata) ((volatile _STC_BIT*)(pdata))->bit3
#define DEF_BIT2(pdata) ((volatile _STC_BIT*)(pdata))->bit2
#define DEF_BIT1(pdata) ((volatile _STC_BIT*)(pdata))->bit1
#define DEF_BIT0(pdata) ((volatile _STC_BIT*)(pdata))->bit0

/* xxx.h */
extern unsigned char status;
...
#define flag_xx4 DEF_BIT4(&status)
#define flag_xx3 DEF_BIT3(&status)
#define flag_xx2 DEF_BIT2(&status)
#define flag_xx1 DEF_BIT1(&status)
#define flag_xx0 DEF_BIT0(&status)

以上来自瑞萨demo。
或者：

union {
    
	struct {
    
		uint8_t flag_xx0	: 1;
		uint8_t flag_xx1	: 1;
		uint8_t flag_xx2	: 1;
		uint8_t flag_xx3	: 1;
		uint8_t rsv			: 4;
	}flag;
	uint8_t flags;
}