eTaskStateGet函数

`eTaskGetState()`函数是FreeRTOS中一个查询任务状态的函数，用于获取任务的当前状态，可以是就绪状态、阻塞状态、运行状态等。

函数原型如下：

eTaskState eTaskGetState( TaskHandle_t xTask );

参数`xTask`是任务句柄，指向要查询状态的任务。

函数返回值为`eTaskState`类型的枚举值，表示任务的状态，具体枚举值如下：

typedef enum
{
    eRunning = 0,           /* The task is in the Running state. */
    eReady,                 /* The task is in the Ready state, or is a suspended task that is just about to enter the Ready state. */
    eBlocked,               /* The task is in the Blocked state. */
    eSuspended,             /* The task is in the Suspended state. */
    eDeleted,               /* The task has been deleted, but its memory has not yet been freed. */
    eInvalid                /* The task handle is not valid. */
} eTaskState;

例如，以下代码可以查询名为"MyTask"的任务的状态，并将其打印出来：

TaskHandle_t xTaskHandle = xTaskGetHandle("MyTask");
if (xTaskHandle != NULL)
{
    eTaskState eState = eTaskGetState(xTaskHandle);
    switch (eState)
    {
        case eRunning:
            printf("Task is running\n");
            break;
        case eReady:
            printf("Task is ready\n");
            break;
        case eBlocked:
            printf("Task is blocked\n");
            break;
        case eSuspended:
            printf("Task is suspended\n");
            break;
        case eDeleted:
            printf("Task is deleted\n");
            break;
        case eInvalid:
            printf("Invalid task handle\n");
            break;
        default:
            printf("Unknown task state\n");
            break;
    }
}

需要注意的是，查询任务状态是一个耗时的操作，因为需要访问任务控制块（TCB），因此应该尽可能避免在中断服务程序中调用该函数。