C++ QLocalSocket真的用于命名管道吗

根据th Qt文档，如果我们想在windows上使用命名管道，我们可以使用QLocalSocket。 我正在用Qt编写一个服务器和客户端程序。如果我尝试使用WIN32 API在管道中写入一些消息，Qt客户端不会显示它。此外，如果客户端再次使用WIN32 API进行写入，则Qt服务器不会回显发送的消息。是否真的建议命名管道使用QLocalSocket

这是Win32服务器代码

     wcout << "Creating an instance of a named pipe..." << endl;
    // Create a pipe to send data
    HANDLE pipe = CreateNamedPipeW(
        L"\\\\.\\pipe\\ServicePipe", // name of the pipe
        PIPE_ACCESS_OUTBOUND, // 1-way pipe -- send only
        PIPE_TYPE_BYTE, // send data as a byte stream
        100, // only allow 1 instance of this pipe
        0, // no outbound buffer
        0, // no inbound buffer
        0, // use default wait time
        NULL // use default security attributes
        );

    if (pipe == NULL || pipe == INVALID_HANDLE_VALUE) {
        wcout << "Failed to create outbound pipe instance.";
        // look up error code here using GetLastError()
        system("pause");
        return 1;
    }

    wcout << "Waiting for a client to connect to the pipe..." << endl;

    // This call blocks until a client process connects to the pipe
    BOOL result = ConnectNamedPipe(pipe, NULL);
    if (!result) {
        wcout << "Failed to make connection on named pipe." << endl;
        // look up error code here using GetLastError()
        CloseHandle(pipe); // close the pipe
        system("pause");
        return 1;
    }

    wcout << "Sending data to pipe..." << endl;

    // This call blocks until a client process reads all the data
    wcout <<endl<<"Input your message: ";

    wstring data=L"";
    getline(wcin,data);
    DWORD numBytesWritten = 0;
    result = WriteFile(
        pipe, // handle to our outbound pipe
        data.c_str(), // data to send
        wcslen(data.c_str()) * sizeof(wchar_t), // length of data to send (bytes)
        &numBytesWritten, // will store actual amount of data sent
        NULL // not using overlapped IO
        );


    if (result) {
        wcout << "Number of bytes sent: " << numBytesWritten << endl;
    } else {
        wcout << "Failed to send data." << endl;
        // look up error code here using GetLastError()
    }

    // Close the pipe (automatically disconnects client too)
    CloseHandle(pipe);

    wcout << "Done." << endl;

---

wcout不必通读所有代码，我可以肯定地回答这个问题。下面是一个工作应用程序中的一些代码，它从一个Qt应用程序写入另一个Qt应用程序中的命名管道（它还原另一个最小化的应用程序）：

要还原的应用程序设置如下：

localServer = new QLocalServer(this);

connect(localServer, SIGNAL(newConnection()), this,
    SLOT(messageFromOtherInstance()));
localServer->listen("Restore Server");

当需要阅读信息时，我会这样做：

QLocalSocket *localSocket = localServer->nextPendingConnection();
if (!localSocket->waitForReadyRead(5000))
{
        qDebug(localSocket->errorString().toLatin1());
        return;
}
QByteArray byteArray = localSocket->readAll();
QString message = QString::fromUtf8(byteArray.constData());

if (message == "raise")
    bringToTop(this);

很可能Qt命名管道和M$命名管道在某种程度上不兼容。我建议编写一个M$framework应用程序来写入M$framework客户端，并编写一个M$framework应用程序来读取，以确保它们都正常工作。然后，替换一个Qt应用程序从Qt服务器读取数据。如果这不起作用，那就是某种框架不兼容（尽管我希望它们都能正确地与操作系统交互）。在这种情况下需要确保的一件事是确保进程不会阻塞。这就是为什么我在阅读之前要确保阅读准备就绪。在M$side上写下之后，您可能还需要冲洗管道，尽管我没有使用Qt

（请注意，我后来发现，如果“打印”、“打印预览”、“页面设置”或“浏览文件”对话框打开，它将停止Qt消息循环，应用程序将对此类消息无响应。选择字体对话框OTOH不会阻止父应用程序。如图所示。）
测试使用的是哪个版本的Windows？是指定命名管道文件的完整路径，还是仅使用文件名？如果只是文件名，可能就是找不到管道。我使用完整路径（\\.\pipe\ServicePipe）Win32代码是如何读取和写入的
QLocalServer
使用
CreateNamedPipeW（…管道类型{U字节}管道读取模式{U字节}管道等待…）创建管道
和
QLocalSocket
连接
CreateFileW（…通用{READ，WRITE}，打开现有…
）。Qt为异步I/O打开管道（
文件标志重叠
）。这意味着您对
ConnectNamedPipe
的调用失败（您没有传递有效的
OVERLAPPED
结构）。同样，您正在本机Windows代码中创建同步I/O管道，但Qt尝试以异步模式连接到它。您必须使用匹配设置。
LocalSocketIpcClient::LocalSocketIpcClient(QString remoteServername, QObject *parent) :
    QObject(parent) {

m_socket = new QLocalSocket(this);
m_serverName = remoteServername;

connect(m_socket, SIGNAL(connected()), this, SLOT(socket_connected()));
connect(m_socket, SIGNAL(disconnected()), this, SLOT(socket_disconnected()));

connect(m_socket, SIGNAL(readyRead()), this, SLOT(socket_readReady()));
connect(m_socket, SIGNAL(error(QLocalSocket::LocalSocketError)),
        this, SLOT(socket_error(QLocalSocket::LocalSocketError)));
}

LocalSocketIpcClient::~LocalSocketIpcClient() {
m_socket->abort();
delete m_socket;
m_socket = NULL;
}

QString LocalSocketIpcClient::Read()
{

QDataStream in(this->m_socket);
in.setVersion(QDataStream::Qt_5_1);

if (m_socket->bytesAvailable() < (int)sizeof(quint16)) {
    return "No data available";
}

QString message;
in >> message;
return message;
}

void LocalSocketIpcClient::send_MessageToServer(QString message) {
m_socket->abort();
m_message = message;
m_socket->connectToServer(m_serverName,QIODevice::ReadWrite);
}


void LocalSocketIpcClient::socket_connected(){
QByteArray block;
QDataStream out(&block, QIODevice::ReadWrite);
out.setVersion(QDataStream::Qt_5_1);
out << m_message;
out.device()->seek(0);
m_socket->write(block);
m_socket->flush();
}

 void LocalSocketIpcClient::socket_disconnected() {
 //showMessage("Client socket_disconnected");
}


void LocalSocketIpcClient::socket_readReady() {
//showMessage("Client socket read Ready");

QDataStream in(this->m_socket);
in.setVersion(QDataStream::Qt_5_1);

if (m_socket->bytesAvailable() < (int)sizeof(quint16)) {
    return;
}

QString message;
in >> message;
emit RecievedDataFromServer(message);

}

void LocalSocketIpcClient::socket_error(QLocalSocket::LocalSocketError e) {
/*
QString errorMessage="Client socket_error:";

switch (e) {
case QLocalSocket::ConnectionRefusedError:
    errorMessage+="The connection was refused by the peer (or timed out).";
    break;

case QLocalSocket::PeerClosedError:
    errorMessage+="The remote socket closed the connection. Note that the client socket (i.e., this socket) will be closed after the remote close notification has been sent.";
    break;

case QLocalSocket::ServerNotFoundError:
    errorMessage+="The local socket name was not found.";
    break;

case QLocalSocket::SocketAccessError:
    errorMessage+="The socket operation failed because the application lacked the required privileges.";
    break;

case QLocalSocket::SocketResourceError:
    errorMessage+="The local system ran out of resources (e.g., too many sockets).";
    break;

case QLocalSocket::SocketTimeoutError:
    errorMessage+="The socket operation timed out.";
    break;

case QLocalSocket::DatagramTooLargeError:
    errorMessage+="The datagram was larger than the operating system's limit (which can be as low as 8192 bytes).";
    break;

case QLocalSocket::ConnectionError:
    errorMessage+="An error occurred with the connection.";
    break;

case QLocalSocket::UnsupportedSocketOperationError:
    errorMessage+="The requested socket operation is not supported by the local operating      system.";
    break;

case QLocalSocket::UnknownSocketError:
    errorMessage+="An unidentified error occurred.";
    break;

default:
    break;
}
showMessage(errorMessage);
*/
}

void LocalSocketIpcClient::showMessage(QString msg)
{
QMessageBox m;
m.setText(msg);
m.exec();
}
LocalSocketIpcClient::SingleMessageSend(QWidget *parent) :
QDialog(parent),
ui(new Ui::SingleMessageSend)
{
ui->setupUi(this);

client  = new LocalSocketIpcClient("\\\\.\\pipe\ServicePipe", this);
connect(this->client,SIGNAL(RecievedDataFromServer(QString)),this,SLOT(UpdateGUI(QString)));
}

LocalSocketIpcClient::~SingleMessageSend()
{
delete ui;
}

void SingleMessageSend::on_pushButton_clicked()
{
QString msg=this->ui->lineEdit->text().trimmed();
client->send_MessageToServer(msg);

}

void SingleMessageSend::UpdateGUI(QString message)
{
 ui->textEdit->insertPlainText(message+"\n");
}

void SingleMessageSend::on_pushButton_2_clicked()
{
ui->textEdit->insertPlainText(client->Read()+QString("\n"));
}

QLocalSocket ls;
ls.connectToServer("Restore Server", QIODevice::WriteOnly);
if (!ls.waitForConnected(5000))
{
        qDebug(ls.errorString().toUtf8());
        return false;
}
ls.write("raise");
if (!ls.waitForBytesWritten(5000))
{
        qDebug(ls.errorString().toUtf8());
        return false;
}
ls.disconnectFromServer();

localServer = new QLocalServer(this);

connect(localServer, SIGNAL(newConnection()), this,
    SLOT(messageFromOtherInstance()));
localServer->listen("Restore Server");

QLocalSocket *localSocket = localServer->nextPendingConnection();
if (!localSocket->waitForReadyRead(5000))
{
        qDebug(localSocket->errorString().toLatin1());
        return;
}
QByteArray byteArray = localSocket->readAll();
QString message = QString::fromUtf8(byteArray.constData());

if (message == "raise")
    bringToTop(this);