QT设置窗口模态 进程调用外部程序和入参

在类中定义成员messhow然后void MainWindow::on_messageaction_triggered(){    messhow.setWindowFlags(Qt::Window);    messhow.setWindowModality(Qt::ApplicationModal);            //模态    messhow.show();}

//ffmpeg

    QProcess ffmpeg_start;

    QStringList arguments;    QString program = "ffmpeg";           //程序放入/usr/local/bin/    arguments<<"-f"<<"video4linux2"<<"-s"<<"320x240"<<"-i"<<"/dev/video0"<</video/video1.avi;    ffmpeg_start.start(program,arguments);