请原子哥进来

suse_lj

我用你开发板中的ucos例程文件 ，我就想建立一个信号量。但是 申请不成功。我单步调试发现，程序进入这个函数
OS_EVENT  *OSSemCreate (INT16U cnt)
{
#if OS_CRITICAL_METHOD == 3                                /* Allocate storage for CPU status register */
    OS_CPU_SR  cpu_sr;
#endif   
    OS_EVENT  *pevent;

    if (OSIntNesting > 0) {                                /* See if called from ISR ...               */
        return ((OS_EVENT *)0);                            /* ... can't CREATE from an ISR             */
    }
    OS_ENTER_CRITICAL();
    pevent = OSEventFreeList;                              /* Get next free event control block        */
    if (OSEventFreeList != (OS_EVENT *)0) {                /* See if pool of free ECB pool was empty   */
        OSEventFreeList = (OS_EVENT *)OSEventFreeList->OSEventPtr;
    }
    OS_EXIT_CRITICAL();
    if (pevent != (OS_EVENT *)0) {                         /* Get an event control block               */
        pevent->OSEventType = OS_EVENT_TYPE_SEM;
        pevent->OSEventCnt  = cnt;                         /* Set semaphore value                      */
        pevent->OSEventPtr  = (void *)0;                   /* Unlink from ECB free list                */
        OS_EventWaitListInit(pevent);                      /* Initialize to 'nobody waiting' on sem.   */
    }
    return (pevent);
}
时，上面函数的最后一个if句，
    if (pevent != (OS_EVENT *)0) {                         /* Get an event control block               */
        pevent->OSEventType = OS_EVENT_TYPE_SEM;
        pevent->OSEventCnt  = cnt;                         /* Set semaphore value                      */
        pevent->OSEventPtr  = (void *)0;                   /* Unlink from ECB free list                */
        OS_EventWaitListInit(pevent);                      /* Initialize to 'nobody waiting' on sem.   */
    }
没有进入 。 好像是没有剩余的事件控制块 。但是 我的#define OS_MAX_EVENTS             20     应该够用了吧 


不知道什么原因 。

正点原子

回复【楼主位】suse_lj:
---------------------------------
我们不是有信号量的例子么？
照我们的操作行不行？