事件标志组用于线程间同步，每一个事件标志组都有31个时间标志位（除最高位）。

 　　osEventFlagsId_t osEventFlagsNew (const osEventFlagsAttr_t *attr)：

　　　　创建一个事件标志组，返回时间标志ID 或者 NULL。不可在中断中调用。

osEventFlagsAttr_t Data Fields
const char *	name	name of the event flags Pointer to a constant string with a human readable name (displayed during debugging) of the event flag object. Default: NULL no name specified.
uint32_t	attr_bits	attribute bits Reserved for future use (must be set to '0' for future compatibility).
void *	cb_mem	memory for control block Pointer to a memory for the event flag control block object. Refer to Static Object Memory for more information. Default: NULL to use Automatic Dynamic Allocation for the event flag control block.
uint32_t	cb_size	size of provided memory for control block The size (in bytes) of memory block passed with cb_mem. For RTX, the minimum value is defined with osRtxEventFlagsCbSize (higher values are permitted). Default: 0 as the default is no memory provided with cb_mem.

　　uint32_t osEventFlagsSet (osEventFlagsId_t ef_id, uint32_t flags)

　　　　设置事件标志组相应flags位。返回设置后标志或者错误码。最高位不可设置。可在中断中调用。

　　uint32_t osEventFlagsWait (osEventFlagsId_t ef_id, uint32_t flags, uint32_t options, uint32_t timeout)

　　　　等待时间标志组相应flags位被设置，默认情况下，该函数返回时，会将相应的等待标志位清零，其他位保持不变。可在中断中调用。

　　　　

Option
osFlagsWaitAny	Wait for any flag (default).
osFlagsWaitAll	Wait for all flags.
osFlagsNoClear	Do not clear flags which have been specified to wait for.

Note：

函数 osEventFlagsSet, osEventFlagsClear, osEventFlagsGet, and osEventFlagsWait 可以在中断中调用。

 1 osEventFlagsId_t evt;
 2 
 3 void
 4 testEventFlags(void)
 5 {
 6     evt = osEventFlagsNew(NULL);
 7     osThreadNew(_ledThread, NULL, NULL); // Create application led thread
 8     osThreadNew(_thread2, NULL, NULL); // Create application segment led thread
 9 }
10 
11 static void
12 _ledThread(void *argument)
13 {
14     (void)argument;
15     uint32_t flags;
16     
17     for(;;) {
18         flags = osEventFlagsWait(evt, 0x00000001, osFlagsWaitAny, osWaitForever);
19         menuShow(&seg_led, flags, 0);
20         
21         flags = osEventFlagsWait(evt, 0x00000002, osFlagsWaitAny, osWaitForever);
22         menuShow(&seg_led, flags, 0);
23         
24         flags = osEventFlagsWait(evt, 0x0000000C, osFlagsWaitAll | osFlagsNoClear, osWaitForever);
25         flags = osEventFlagsGet(evt);
26         menuShow(&seg_led, flags, 0);
27         osEventFlagsClear (evt, 0x0000000C);
28         
29         flags = osEventFlagsWait(evt, 0x00000007, osFlagsWaitAll, osWaitForever);
30         menuShow(&seg_led, flags, 0);
31     }
32 }
33 
34 static void
35 _thread2(void *argument)
36 {
37     (void)argument;
38     for(;;) {
39         osEventFlagsSet(evt, 0x00000001);
40         osDelay(1000);
41         
42         osEventFlagsSet(evt, 0x00000002);
43         osDelay(1000);
44         
45         osEventFlagsSet(evt, 0x0000000C);
46         osDelay(1000);
47         
48         osEventFlagsSet(evt, 0x00000007);
49         osDelay(1000);
50     }
51 }