Question

ucos邮箱疑问

void *OSMboxPend (OS_EVENT *pevent, INT16U timeout, INT8U *err)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif
void *msg;

if (OSIntNesting > 0) { /* See if called from ISR ... */
*err = OS_ERR_PEND_ISR; /* ... can't PEND from an ISR */
return ((void *)0);
}
#if OS_ARG_CHK_EN > 0
if (pevent == (OS_EVENT *)0) { /* Validate 'pevent' */
*err = OS_ERR_PEVENT_NULL;
return ((void *)0);
}
#endif
if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) { /* Validate event block type */
*err = OS_ERR_EVENT_TYPE;
return ((void *)0);
}
OS_ENTER_CRITICAL();
msg = pevent->OSEventPtr;
if (msg != (void *)0) { /* See if there is already a message */
pevent->OSEventPtr = (void *)0; /* Clear the mailbox */
OS_EXIT_CRITICAL();
*err = OS_NO_ERR;
return (msg); /* Return the message received (or NULL) */
}
这是ucos中的等待邮箱，倒数第二行return（msg）是返回到何处啊？函数名定义成了void，我改怎么访问这个msg呢？

Answer 1

返回的是一个函数