void MainWindow::addimageSlot()
{
    if(memory.isAttached())
    {
        memory.detach();//如有共享内存则删除，将共享内存与程序分离
    }
    QString openFileName = QFileDialog::getOpenFileName(this,"打开文件",QDir::currentPath(),"文件(*.jpg *.png *.bmp)");
    QImage image;
    if (!image.load(openFileName))
    {
       ui->imageLabel->setText("Selected file is not an image, please select another.");
       return;
    }
    ui->imageLabel->setPixmap(QPixmap::fromImage(image));//QPixmap与QImage见下
    //先申请一个缓冲区，将图片加载到缓冲区，利用memcpy将缓冲区的内容copy到共享内存
    //中间注意size
    //将图片加入到一块缓冲区
    QBuffer buffer;
    buffer.open(QBuffer::ReadWrite);//设置读写属性
    QDataStream out(&buffer);//设置数据流，指向buffer
    out<<image;//将图片通过文件流存入buffer
    //判断
    int size  = buffer.size();
    if (!memory.create(size))
    {
        ui->imageLabel->setText("不能创造共享内存！");
//        qDebug()<<memory.errorString();
        return ;
    }
    //从缓冲区到共享内存
    memory.lock();
    char *to = (char*)memory.data();//返回一个共享内存内容的指针
    const char *from = buffer.data().data();
    memcpy(to,from,qMin(memory.size(),size));
    memory.unlock();
}

void MainWindow::getMemorySlot()
{
    //判断共享内存是否存在
    if(!memory.attach())
    {
        ui->imageLabel->setText("无共享内存，请先加载一个图片");
        return;
    }
    QBuffer buffer;
    QDataStream in(&buffer);
    QImage image;
    memory.lock();
    buffer.setData((char*)memory.constData(),memory.size());//
    buffer.open(QBuffer::ReadOnly);
    in>>image;
    memory.unlock();
    memory.detach();//分离，删除
    ui->imageLabel->setPixmap(QPixmap::fromImage(image));
}