异步读
异步与同步的概念：同步：必须等待函数执行的操作完成，才返回
异步：只发送请求，不用等待函数执行完成，立即返回
异步的实现：
HANDLE g_hOverlappedEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
OVERLAPPED Overlapped;
memset(&Overlapped, 0, sizeof(OVERLAPPED));
ULONG ulRet= 0;
Overlapped.hEvent = g_hOverlappedEvent;
ulRet = ReadFile(gh_Device, &OpInfo, sizeof(OP_INFO), &ulBytesReturn, &Overlapped);
if (ulRet == 0)
{
if (GetLastError() == ERROR_IO_PENDING)
{
ULONG ulReturn = WaitForSingleObject(Overlapped.hEvent, INFINITE);
if (ulReturn == WAIT_FAILED)
{
break;
}
}
}
具体的可以参考这篇文章
http://www.blogfshare.com/irp-synchronization-asynchronous.html
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