设置重叠串口通信的困难

Question

我正在努力通过串口COM端口与设备通信。

起初，我设法通过一个非常简单的非重叠设置来读取和写入端口。但现在我意识到我在WRITE和READ函数之间有一个约100ms的延迟。

问题：我需要在大约15ms后检查答案才能立即回复。

我不知道如何实现这一点，所以我尝试设置重叠的通信并遇到了这个Microsoft文档：Serial Communications

现在我甚至无法让READ部分工作。

这是我现在的代码

int main() {
    LPCWSTR port = L"COM3:";

    HANDLE hComm = CreateFile(port, GENERIC_READ | GENERIC_WRITE, 0, 0, OPEN_EXISTING, FILE_FLAG_OVERLAPPED, 0);
    if (hComm == INVALID_HANDLE_VALUE) cout << "ERROR " << GetLastError() << endl;
    else {
        DWORD dwRead;
        DWORD dwRes;
        BOOL fWaitingOnRead = FALSE;
        OVERLAPPED osReader = { 0 };

        //Create overlapped event
        osReader.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
        if (osReader.hEvent == NULL) cout << "ERROR " << GetLastError() << endl;
        else {
            BYTE Byte[2];
            while (true) {
                if (!fWaitingOnRead) {
                    //Issue read operation
                    if (!ReadFile(hComm, &Byte, sizeof(Byte), &dwRead, &osReader)); cout << "ERROR " << GetLastError() << endl;
                    else {
                        cout << std::hex << (int)Byte[0] << " " << std::hex << (int)Byte[1] << endl;
                        fWaitingOnRead = TRUE;
                    }
                }
                else {
                    dwRes = WaitForSingleObject(osReader.hEvent, 500);
                    switch (dwRes) {
                        // Read completed.
                        case WAIT_OBJECT_0:
                            if (!GetOverlappedResult(hComm, &osReader, &dwRead, FALSE)) cout << "ERROR " << GetLastError() << endl;
                            else {
                                cout << std::hex << (int)Byte[0] << " " << std::hex << (int)Byte[1] << endl;
                            }

                            //  Reset flag so that another opertion can be issued.
                            fWaitingOnRead = FALSE;
                            break;

                        default:
                            break;
                    }
                }

                Sleep(100);
            }
        }
    }
    return 0;
}

此代码应将READ函数的结果输出到控制台。但它每次都失败，GetLastError（）给我 997

我希望有人可以指出我的错误，或者给我一个提示如何解决这个重叠的结构，我还不太清楚。