编程实例

1. 在任务Example_TaskEntry创建任务Example_Event，其中任务Example_Event优先级高于Example_TaskEntry。
2. 在任务Example_Event中读事件0x00000001，阻塞，发生任务切换，执行任务Example_TaskEntry。
3. 在任务Example_TaskEntry向任务Example_Event写事件0x00000001，发生任务切换，执行任务Example_Event。
4. Example_Event得以执行，直到任务结束。
5. Example_TaskEntry得以执行，直到任务结束。

#include "los_event.h"
#include "los_task.h"
#include "securec.h"

/* 任务ID */
UINT32 g_testTaskId;

/* 事件控制结构体 */
EVENT_CB_S g_exampleEvent;

/* 等待的事件类型 */
#define EVENT_WAIT 0x00000001

/* 用例任务入口函数 */
VOID Example_Event(VOID)
{
    UINT32 ret;
    UINT32 event;

    /* 超时等待方式读事件,超时时间为100 ticks, 若100 ticks后未读取到指定事件，读事件超时，任务直接唤醒 */
    printf("Example_Event wait event 0x%x \n", EVENT_WAIT);

    event = LOS_EventRead(&g_exampleEvent, EVENT_WAIT, LOS_WAITMODE_AND, 100);
    if (event == EVENT_WAIT) {
        printf("Example_Event,read event :0x%x\n", event);
    } else {
        printf("Example_Event,read event timeout\n");
    }
}

UINT32 Example_TaskEntry(VOID)
{
    UINT32 ret;
    TSK_INIT_PARAM_S task1;

    /* 事件初始化 */
    ret = LOS_EventInit(&g_exampleEvent);
    if (ret != LOS_OK) {
        printf("init event failed .\n");
        return -1;
    }

    /* 创建任务 */
    (VOID)memset_s(&task1, sizeof(TSK_INIT_PARAM_S), 0, sizeof(TSK_INIT_PARAM_S));
    task1.pfnTaskEntry = (TSK_ENTRY_FUNC)Example_Event;
    task1.pcName       = "EventTsk1";
    task1.uwStackSize  = OS_TSK_DEFAULT_STACK_SIZE;
    task1.usTaskPrio   = 5;
    ret = LOS_TaskCreate(&g_testTaskId, &task1);
    if (ret != LOS_OK) {
        printf("task create failed .\n");
        return LOS_NOK;
    }

    /* 写g_testTaskId 等待事件 */
    printf("Example_TaskEntry write event .\n");

    ret = LOS_EventWrite(&g_exampleEvent, EVENT_WAIT);
    if (ret != LOS_OK) {
        printf("event write failed .\n");
        return LOS_NOK;
    }

    /* 清标志位 */
    printf("EventMask:%d\n", g_exampleEvent.uwEventID);
    LOS_EventClear(&g_exampleEvent, ~g_exampleEvent.uwEventID);
    printf("EventMask:%d\n", g_exampleEvent.uwEventID);

    /* 删除任务 */
    ret = LOS_TaskDelete(g_testTaskId);
    if (ret != LOS_OK) {
        printf("task delete failed .\n");
        return LOS_NOK;
    }

    return LOS_OK;
}

Example_Event wait event 0x1 
Example_TaskEntry write event .
Example_Event,read event :0x1
EventMask:1
EventMask:0