Skip to content
  • Categories
  • Recent
  • Tags
  • Popular
  • Users
  • Groups
  • Search
  • Get Qt Extensions
  • Unsolved
Collapse
Brand Logo
  1. Home
  2. Qt Development
  3. General and Desktop
  4. Regarding QProcess:: Not able to read data from the console
Qt 6.11 is out! See what's new in the release blog

Regarding QProcess:: Not able to read data from the console

Scheduled Pinned Locked Moved Solved General and Desktop
27 Posts 5 Posters 16.8k Views 2 Watching
  • Oldest to Newest
  • Newest to Oldest
  • Most Votes
Reply
  • Reply as topic
Log in to reply
This topic has been deleted. Only users with topic management privileges can see it.
  • VRoninV Offline
    VRoninV Offline
    VRonin
    wrote on last edited by
    #17

    If what you are reading are strings then you can manipulate them the usual way, for example:

    const QString processOut = QString::fromLatin1(myProcess->readAllStandardError());
    const QRegularExpression regXp("MyField: (\\S+)");
    const auto regXpMatch = regXp.match(processOut);
    if(regXpMatch.hasMatch()){
    qDebug() << "Output: "<< regXpMatch.captured(1);
    }
    

    "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
    ~Napoleon Bonaparte

    On a crusade to banish setIndexWidget() from the holy land of Qt

    Naveen_DN 1 Reply Last reply
    0
    • VRoninV VRonin

      If what you are reading are strings then you can manipulate them the usual way, for example:

      const QString processOut = QString::fromLatin1(myProcess->readAllStandardError());
      const QRegularExpression regXp("MyField: (\\S+)");
      const auto regXpMatch = regXp.match(processOut);
      if(regXpMatch.hasMatch()){
      qDebug() << "Output: "<< regXpMatch.captured(1);
      }
      
      Naveen_DN Offline
      Naveen_DN Offline
      Naveen_D
      wrote on last edited by Naveen_D
      #18

      @VRonin sorry i didn't get the the regular exp part...
      the actual scenario is, i will give the input at runtime via live microphone when the other process is started by this current Qprocess...and in that started process i am storing the input in a string and displaying through qDebug. those debug statements from the started process are now copied to my console, from which i need to take a particular string and pass it through a signal.

      Naveen_D

      VRoninV 1 Reply Last reply
      0
      • Naveen_DN Naveen_D

        @VRonin sorry i didn't get the the regular exp part...
        the actual scenario is, i will give the input at runtime via live microphone when the other process is started by this current Qprocess...and in that started process i am storing the input in a string and displaying through qDebug. those debug statements from the started process are now copied to my console, from which i need to take a particular string and pass it through a signal.

        VRoninV Offline
        VRoninV Offline
        VRonin
        wrote on last edited by VRonin
        #19

        @Naveen_D said in Regarding QProcess:: Not able to read data from the console:

        which i need to take a particular string

        I don't know how you identify the particular string so I just guessed a use based off a regular expression. what I mean is that instead of passing whatever you receive to your console with qDebug()<<"Output: "<< myProcess->readAllStandardOutput(); you can do whatever you want with the read data. For example, if you want to pass every line you receive to a signal you can use:

        connect(myProcess,&QProcess::readyReadStandardError,[myProcess,this]()->void{
        const QByteArray readData= myProcess->readAllStandardError();
        QTextStream lineReader(readData);
        QString tempLine;
        while (lineReader.readLineInto(&tempLine)) {
        /*emit*/ mySignal(tempLine);
        }
                });
        

        "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
        ~Napoleon Bonaparte

        On a crusade to banish setIndexWidget() from the holy land of Qt

        Naveen_DN 1 Reply Last reply
        0
        • VRoninV VRonin

          @Naveen_D said in Regarding QProcess:: Not able to read data from the console:

          which i need to take a particular string

          I don't know how you identify the particular string so I just guessed a use based off a regular expression. what I mean is that instead of passing whatever you receive to your console with qDebug()<<"Output: "<< myProcess->readAllStandardOutput(); you can do whatever you want with the read data. For example, if you want to pass every line you receive to a signal you can use:

          connect(myProcess,&QProcess::readyReadStandardError,[myProcess,this]()->void{
          const QByteArray readData= myProcess->readAllStandardError();
          QTextStream lineReader(readData);
          QString tempLine;
          while (lineReader.readLineInto(&tempLine)) {
          /*emit*/ mySignal(tempLine);
          }
                  });
          
          Naveen_DN Offline
          Naveen_DN Offline
          Naveen_D
          wrote on last edited by
          #20

          @VRonin As said by you i am trying with Regular Exp,
          the output at present i am getting is ...
          Output: "loaded file >>>>>>> 0x1c57220 \n\n"
          Output: "Recognition instance >>>>> 0x1c58660 \n\n"
          Output: "\n<<< please speak >>> \n\n \n\n"
          Output: "Sentence :\nchar *data>>>>>>> <s> \n\nchar *data>>>>>>> WORLD \n\nchar *data>>>>>>> </s> \n\nReceived Command: "WORLD" \n\n"

          from this output i want to select the part which is in bold... but when i run my program and give output through a microphone i get the above output in my console...but i am not getting the regular exp qDebug part.

          Naveen_D

          1 Reply Last reply
          0
          • VRoninV Offline
            VRoninV Offline
            VRonin
            wrote on last edited by
            #21

            What is your current code?

            Also, if you have access to the source of the voice recognition software you can send data directly in raw format (using toBase64()) and receive it more easily

            "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
            ~Napoleon Bonaparte

            On a crusade to banish setIndexWidget() from the holy land of Qt

            Naveen_DN 2 Replies Last reply
            0
            • VRoninV VRonin

              What is your current code?

              Also, if you have access to the source of the voice recognition software you can send data directly in raw format (using toBase64()) and receive it more easily

              Naveen_DN Offline
              Naveen_DN Offline
              Naveen_D
              wrote on last edited by
              #22

              @VRonin said in Regarding QProcess:: Not able to read data from the console:

              Also, if you have access to the source of the voice recognition software you can send data directly in raw format (using toBase64()) and receive it more easily

              First i tried using directly and was able to send the output through the signal...but voice recognition has some callback functions which does not return control back to the function from where it is called so...i made this voice recog as a separate process.

              Naveen_D

              1 Reply Last reply
              0
              • VRoninV VRonin

                What is your current code?

                Also, if you have access to the source of the voice recognition software you can send data directly in raw format (using toBase64()) and receive it more easily

                Naveen_DN Offline
                Naveen_DN Offline
                Naveen_D
                wrote on last edited by
                #23

                @VRonin said in Regarding QProcess:: Not able to read data from the console:

                What is your current code?

                #include "ProcessWidget.h"
                
                ProcessWidget::ProcessWidget(QWidget *parent)
                    : QWidget(parent)
                {
                    m_btn= new QPushButton("click here",this);
                    connect(m_btn,SIGNAL(clicked()),this,SLOT(vStartProcess()));
                }
                
                void ProcessWidget::vStartProcess()
                {
                    qDebug()<<"entered the function"<<endl;
                    const QString program = QStringLiteral("/home/ubuntu/Documents/Sample_Examples_Qt_Qml/VoiceRecognition/VoiceRecognition");
                    QProcess* myProcess = new QProcess;
                //    connect(myProcess,&QProcess::readyReadStandardOutput,[myProcess]()->void{
                //                qDebug()<<"Output: "<< myProcess->readAllStandardOutput()<<endl;
                //            });
                    connect(myProcess,&QProcess::readyReadStandardError,[myProcess]()->void{
                                qDebug()<<"Output: "<< myProcess->readAllStandardError();
                                const QString processOut = QString::fromLatin1(myProcess->readAllStandardError());
                                const QRegularExpression regXp("Received Command");
                                const auto regXpMatch = regXp.match(processOut);
                                if(regXpMatch.hasMatch()){
                                    qDebug() << "Output of regular exp is: "<< regXpMatch.captured(1);
                                }
                            });
                    connect(myProcess,SIGNAL(finished(int)),myProcess,SLOT(deleteLater()));
                    myProcess->start(program);
                    qDebug()<<"process started waiting for output"<<endl;
                    connect(this,&ProcessWidget::destroyed,myProcess,&QProcess::kill);
                
                }
                
                

                Naveen_D

                1 Reply Last reply
                0
                • VRoninV Offline
                  VRoninV Offline
                  VRonin
                  wrote on last edited by
                  #24

                  I guess you are not really familiar with the perl regular expression syntax.
                  const QRegularExpression regXp("Received Command"); should be const QRegularExpression regXp("Received Command:\\s*(.+)");

                  "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
                  ~Napoleon Bonaparte

                  On a crusade to banish setIndexWidget() from the holy land of Qt

                  Naveen_DN 1 Reply Last reply
                  1
                  • VRoninV VRonin

                    I guess you are not really familiar with the perl regular expression syntax.
                    const QRegularExpression regXp("Received Command"); should be const QRegularExpression regXp("Received Command:\\s*(.+)");

                    Naveen_DN Offline
                    Naveen_DN Offline
                    Naveen_D
                    wrote on last edited by
                    #25

                    @VRonin thanks for the reply...i got the output as expected.
                    but the output which i am getting is appending with (" ") and \ y is it like that ? and how to remove this double quotes and \ ?

                    Naveen_D

                    jsulmJ 1 Reply Last reply
                    0
                    • Naveen_DN Naveen_D

                      @VRonin thanks for the reply...i got the output as expected.
                      but the output which i am getting is appending with (" ") and \ y is it like that ? and how to remove this double quotes and \ ?

                      jsulmJ Offline
                      jsulmJ Offline
                      jsulm
                      Lifetime Qt Champion
                      wrote on last edited by
                      #26

                      @Naveen_D The double-quotes are comming from qDebug(), they are not really in your string (you can try with std::cout to verify).

                      https://forum.qt.io/topic/113070/qt-code-of-conduct

                      Naveen_DN 1 Reply Last reply
                      0
                      • jsulmJ jsulm

                        @Naveen_D The double-quotes are comming from qDebug(), they are not really in your string (you can try with std::cout to verify).

                        Naveen_DN Offline
                        Naveen_DN Offline
                        Naveen_D
                        wrote on last edited by
                        #27

                        @jsulm yes sir i got that...thanks for the information

                        Naveen_D

                        1 Reply Last reply
                        0

                        • Login

                        • Login or register to search.
                        • First post
                          Last post
                        0
                        • Categories
                        • Recent
                        • Tags
                        • Popular
                        • Users
                        • Groups
                        • Search
                        • Get Qt Extensions
                        • Unsolved