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- 537
- 金钱
- 537
- 注册时间
- 2013-8-9
- 在线时间
- 3 小时
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5金钱
请问请问删除信号量的时候,等待任务就绪,为什么赋予标志是OS_STAT_PEND_OK,这样岂不是跟正常的申请到信号量没两样,就这一条语句
case OS_DEL_ALWAYS: /* Always delete the semaphore */
while (pevent->OSEventGrp != 0u) { /* Ready ALL tasks waiting for semaphore */
(void)OS_EventTaskRdy(pevent, (void *)0, OS_STAT_SEM, OS_STAT_PEND_OK);
}
OS_EVENT *OSSemDel (OS_EVENT *pevent,
INT8U opt,
INT8U *perr)
{
BOOLEAN tasks_waiting;
OS_EVENT *pevent_return;
#if OS_CRITICAL_METHOD == 3u /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr = 0u;
#endif
#ifdef OS_SAFETY_CRITICAL
if (perr == (INT8U *)0) {
OS_SAFETY_CRITICAL_EXCEPTION();
}
#endif
#if OS_ARG_CHK_EN > 0u
if (pevent == (OS_EVENT *)0) { /* Validate 'pevent' */
*perr = OS_ERR_PEVENT_NULL;
return (pevent);
}
#endif
if (pevent->OSEventType != OS_EVENT_TYPE_SEM) { /* Validate event block type */
*perr = OS_ERR_EVENT_TYPE;
return (pevent);
}
if (OSIntNesting > 0u) { /* See if called from ISR ... */
*perr = OS_ERR_DEL_ISR; /* ... can't DELETE from an ISR */
return (pevent);
}
OS_ENTER_CRITICAL();
if (pevent->OSEventGrp != 0u) { /* See if any tasks waiting on semaphore */
tasks_waiting = OS_TRUE; /* Yes */
} else {
tasks_waiting = OS_FALSE; /* No */
}
switch (opt) {
case OS_DEL_NO_PEND: /* Delete semaphore only if no task waiting */
if (tasks_waiting == OS_FALSE) {
#if OS_EVENT_NAME_EN > 0u
pevent->OSEventName = (INT8U *)(void *)"?";
#endif
pevent->OSEventType = OS_EVENT_TYPE_UNUSED;
pevent->OSEventPtr = OSEventFreeList; /* Return Event Control Block to free list */
pevent->OSEventCnt = 0u;
OSEventFreeList = pevent; /* Get next free event control block */
OS_EXIT_CRITICAL();
*perr = OS_ERR_NONE;
pevent_return = (OS_EVENT *)0; /* Semaphore has been deleted */
} else {
OS_EXIT_CRITICAL();
*perr = OS_ERR_TASK_WAITING;
pevent_return = pevent;
}
break;
case OS_DEL_ALWAYS: /* Always delete the semaphore */
while (pevent->OSEventGrp != 0u) { /* Ready ALL tasks waiting for semaphore */
(void)OS_EventTaskRdy(pevent, (void *)0, OS_STAT_SEM, OS_STAT_PEND_OK);
}
#if OS_EVENT_NAME_EN > 0u
pevent->OSEventName = (INT8U *)(void *)"?";
#endif
pevent->OSEventType = OS_EVENT_TYPE_UNUSED;
pevent->OSEventPtr = OSEventFreeList; /* Return Event Control Block to free list */
pevent->OSEventCnt = 0u;
OSEventFreeList = pevent; /* Get next free event control block */
OS_EXIT_CRITICAL();
if (tasks_waiting == OS_TRUE) { /* Reschedule only if task(s) were waiting */
OS_Sched(); /* Find highest priority task ready to run */
}
*perr = OS_ERR_NONE;
pevent_return = (OS_EVENT *)0; /* Semaphore has been deleted */
break;
default:
OS_EXIT_CRITICAL();
*perr = OS_ERR_INVALID_OPT;
pevent_return = pevent;
break;
}
return (pevent_return);
}
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最佳答案
查看完整内容[请看2#楼]
回复【2楼】zuozhongkai:
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哈哈,我想明白了,信号量不存在了,可资源还在,就绪之后访问资源不存在矛盾
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