我希望在提供I / O完成例程的asynchronous模式下使用函数ReadDirectoryChangesW() 。
问题是我不知道如何检索完成例程（ CALLBACK函数）中有关更改的确切信息。 完成程序定义如下：
VOID CALLBACK FileIOCompletionRoutine( [in] DWORD dwErrorCode, [in] DWORD dwNumberOfBytesTransfered, [in] LPOVERLAPPED lpOverlapped );
我不知道信息包含在LPOVERLAPPED结构中。 但我不知道如何得到它。
很好的问题！ 这已经晚了7年，但是这里有一些答案，或者更重要的是， 如何找到答案。 所以，ReadDirectoryChangesW的文档：
https://msdn.microsoft.com/en-us/library/windows/desktop/aa365465%28v=vs.85%29.aspx
在参数部分给出一个到FileIOCompletionRoutine的链接：
https://msdn.microsoft.com/en-us/library/windows/desktop/aa364052%28v=vs.85%29.aspx
在“示例”部分给出了使用完成例程的命名管道服务器的链接：
https://msdn.microsoft.com/en-us/library/windows/desktop/aa365601%28v=vs.85%29.aspx
它相信或者不相信甚至不使用ReadDirectoryChangesW，但实际上给出了一个使用ReadFileEx的例子，它也使用FileIOCompletionRoutine：
https://msdn.microsoft.com/en-us/library/windows/desktop/aa365468%28v=vs.85%29.aspx
你可以在这段代码中看到使用这两个函数（ReadFileEx和CompletedReadRoutine（这是应用程序定义的回调函数FileIOCompletionRoutine的实现））的例子：
// CompletedWriteRoutine(DWORD, DWORD, LPOVERLAPPED) // This routine is called as a completion routine after writing to // the pipe, or when a new client has connected to a pipe instance. // It starts another read operation. VOID WINAPI CompletedWriteRoutine(DWORD dwErr, DWORD cbWritten, LPOVERLAPPED lpOverLap) { LPPIPEINST lpPipeInst; BOOL fRead = FALSE; // lpOverlap points to storage for this instance. lpPipeInst = (LPPIPEINST) lpOverLap; // The write operation has finished, so read the next request (if // there is no error). if ((dwErr == 0) && (cbWritten == lpPipeInst->cbToWrite)) fRead = ReadFileEx( lpPipeInst->hPipeInst, lpPipeInst->chRequest, BUFSIZE*sizeof(TCHAR), (LPOVERLAPPED) lpPipeInst, (LPOVERLAPPED_COMPLETION_ROUTINE) CompletedReadRoutine); // Disconnect if an error occurred. if (! fRead) DisconnectAndClose(lpPipeInst); } // CompletedReadRoutine(DWORD, DWORD, LPOVERLAPPED) // This routine is called as an I/O completion routine after reading // a request from the client. It gets data and writes it to the pipe. VOID WINAPI CompletedReadRoutine(DWORD dwErr, DWORD cbBytesRead, LPOVERLAPPED lpOverLap) { LPPIPEINST lpPipeInst; BOOL fWrite = FALSE; // lpOverlap points to storage for this instance. lpPipeInst = (LPPIPEINST) lpOverLap; // The read operation has finished, so write a response (if no // error occurred). if ((dwErr == 0) && (cbBytesRead != 0)) { GetAnswerToRequest(lpPipeInst); fWrite = WriteFileEx( lpPipeInst->hPipeInst, lpPipeInst->chReply, lpPipeInst->cbToWrite, (LPOVERLAPPED) lpPipeInst, (LPOVERLAPPED_COMPLETION_ROUTINE) CompletedWriteRoutine); } // Disconnect if an error occurred. if (! fWrite) DisconnectAndClose(lpPipeInst); }
这不是一个很好的答案（我只是在探讨是否我甚至想要使用这些功能），但它应该帮助人们开始。
也可以看看：
https://msdn.microsoft.com/en-us/library/windows/desktop/aa365261%28v=vs.85%29.aspx