OVERLAPPED变量能用多次吗？？？

我用OVERLAPPED变量使得我的线程能与VxD程序进行异步数据交换，第一个线程工作的很好，可是第二个线程一运行就死机。我的程序如下：
1。页锁定部分
case DIOC_EVENTTHREAD:
if (!pDIOCParams->dioc_ovrlp) break;
TemOverLap= (PCHAR)LinPageLock( PAGENUM(pDIOCParams->dioc_ovrlp),
_NPAGES_(pDIOCParams->dioc_ovrlp, sizeof(OVERLAPPED)),
PAGEMAPGLOBAL);
EOverLap=(OVERLAPPED *) (TemOverLap+((ULONG)pDIOCParams->dioc_ovrlp  & 0xfff));
break;
2。通知应用程序，并释放页锁定部分
VWIN32_DIOCCompletionRoutine(EOverLap->O_Internal);
LinPageUnLock(PAGENUM(EOverLap),_NPAGES_(EOverLap, sizeof(OVERLAPPED)),PAGEMAPGLOBAL);

3。应用程序部分
DeviceIoControl(hPort,DIOC_EVENTTHREAD,NULL,0,NULL,0,NULL,&EOverLap);
        GetOverlappedResult(hPort,&EOverLap,&Event,TRUE);
4。宏定义
#define PAGENUM(p) (((ULONG(p))>>12)
#define _NPAGES_(p,k) ((PAGENUM((char*)p+(k-1))-PAGENUM(p))+1)
请问各位高手，我这样做有什么错误吗？谢谢了！

[编辑 -  12/25/01 作者： w00d]

大致看起来没有什么错误，和vtoolsd的sample一样。但有一点要提醒你：最好在每个线程里面“各自“打开/关闭vxd，否则会翘掉。