做I/O完成端口时是否需要在OVERLAPPED结构上设置hEvent？
我在 Windows 上使用 I/O 完成端口进行串行端口通信（我们可能会大量使用串行端口）。我已经完成了通常的操作，创建 IOCP，启动 I/O 线程，并将我的 CreateFile() 句柄与 IOCP 关联起来（CreateFile() 是通过以下方式调用的FILE_FLAG_OVERLAPPED）。这一切都工作正常。我已将 COMMTIMEOUTS 全部设置为 0，但 ReadIntervalTimeout 除外，它设置为 MAXDWORD 以实现完全异步。
在我的 I/O 线程中，我注意到 GetQueuedCompletionStatus() 无限期地阻塞。我正在使用 INFINITE 超时。因此，在将句柄与 IOCP 关联后，我立即调用了 ReadFile() 。现在，这会导致 GetQueuedCompletionStatus() 由于某种原因立即释放并传输 0 个字节，但没有错误（它返回 true，GetLastError() 报告 0）。如果没有什么可做的，我显然希望它被阻止。如果我在 GetQueuedCompletionStatus() 之后放置另一个 ReadFile()，那么池中的另一个线程将拾取它并传输 0 字节并且没有错误。
在我看到和遵循的示例中，我没有看到任何人在使用 IOCP 时在 OVERLAPPED 结构上设置 hEvent。有必要吗？我不关心阻塞 IOCP 线程——所以我永远不会对 CreateEvent(...) | 感兴趣。 1..
如果没有必要，可能是什么原因造成的？ GetQueuedCompletionStatus() 需要阻塞，直到数据到达串行端口。
有没有好的 IOCP 串口示例？我还没有找到完整的串行端口+ IOCP 示例。大多数都是用于套接字的。理论上，它应该适用于串行端口、文件、套接字等。
I'm using I/O completion ports on Windows for serial port communication (we will potentially have lots and lots of serial port usage). I've done the usual, creating the IOCP, spinning up the I/O threads, and associating my CreateFile() handle with the IOCP (CreateFile() was called with FILE_FLAG_OVERLAPPED). That's all working fine. I've set the COMMTIMEOUTS all to 0 except ReadIntervalTimeout which is set to MAXDWORD in order to be completely async.
In my I/O thread, I've noticed that GetQueuedCompletionStatus() blocks indefinitely. I'm using an INFINITE timeout. So I put a ReadFile() call right after I associate my handle with the IOCP. Now that causes GetQueuedCompletionStatus() to release immediately for some reason with 0 bytes transferred, but there's no errors (it returns true, GetLastError() reports 0). I obviously want it to block if there's nothing for it to do. If I put another ReadFile() after GetQueuedCompletionStatus(), then another thread in the pool will pick it up with 0 bytes transferred and no errors.
In the examples I've seen and followed, I don't see anyone setting the hEvent on the OVERLAPPED structure when using IOCP. Is that necessary? I don't care to ever block IOCP threads -- so I'll never be interested in CreateEvent(...) | 1.
If it's not necessary, what could be causing the problem? GetQueuedCompletionStatus() needs to block until data arrives on the serial port.
Are there any good IOCP serial port examples out there? I haven't found a complete serial port + IOCP example out there. Most of them are for sockets. In theory, it should work for serial ports, files, sockets, etc.
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我发现了——我没有用
EV_RXCHAR | 调用，然后使用SetCommMask()EV_TXEMPTYOVERLAPPED结构的WaitCommEvent()。完成此操作后，我的 IOCP 线程的行为符合预期。当端口上出现新字符时，GetQueuedCompletionStatus()返回。然后我可以调用ReadFile()。所以回答原来的问题：“不，你不需要为串口的IOCP设置hEvent。”
I figured it out -- I wasn't calling
SetCommMask()withEV_RXCHAR | EV_TXEMPTYand thenWaitCommEvent()with theOVERLAPPEDstruct. After I did that, my IOCP threads behaved as expected.GetQueuedCompletionStatus()returned when a new character appeared on the port. I could then callReadFile().So to answer the original question: "no, you don't need to set hEvent for IOCP with serial ports."