creat.txt

来自「20080718μC_OS－Ⅱ实时嵌入式操作系统源代码」· 文本 代码 · 共 37 行

#if OS_TASK_CREATE_EN
INT8U OSTaskCreate (void (*task)(void *pd), void *pdata, OS_STK *ptos, INT8U prio)
{
    void   *psp;
    INT8U   err;


    if (prio > OS_LOWEST_PRIO) {             /* Make sure priority is within allowable range           */
        return (OS_PRIO_INVALID);
    }
    OS_ENTER_CRITICAL();
    if (OSTCBPrioTbl[prio] == (OS_TCB *)0) { /* Make sure task doesn't already exist at this priority  */
        OSTCBPrioTbl[prio] = (OS_TCB *)1;    /* Reserve the priority to prevent others from doing ...  */
                                             /* ... the same thing until task is created.              */
        OS_EXIT_CRITICAL();
        psp = (void *)OSTaskStkInit(task, pdata, ptos, 0); /* Initialize the task's stack              */
        err = OSTCBInit(prio, psp, (void *)0, 0, 0, (void *)0, 0);         
        if (err == OS_NO_ERR) {
            OS_ENTER_CRITICAL();
            OSTaskCtr++;                                   /* Increment the #tasks counter             */
            OSTaskCreateHook(OSTCBPrioTbl[prio]);          /* Call user defined hook                   */
            OS_EXIT_CRITICAL();
            if (OSRunning) {                 /* Find highest priority task if multitasking has started */
                OSSched();
            }
        } else {
            OS_ENTER_CRITICAL();
            OSTCBPrioTbl[prio] = (OS_TCB *)0;/* Make this priority available to others                 */
            OS_EXIT_CRITICAL();
        }
        return (err);
    } else {
        OS_EXIT_CRITICAL();
        return (OS_PRIO_EXIST);
    }
}
#endif