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. problem with System()
Forum Update on Monday, May 27th 2025

problem with System()

Scheduled Pinned Locked Moved Unsolved General and Desktop
system commandsystem
37 Posts 5 Posters 12.5k Views
  • 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.
  • SGaistS SGaist

    You call it with a path relative to where you main application is started.

    ./home/princi is equivalent to $PWD/home/princi/ which is likely not what you want, is it ?

    AlvaroSA Offline
    AlvaroSA Offline
    AlvaroS
    wrote on last edited by
    #11

    @SGaist Now I do this and nothing as well..

        QString program = "princi";
        QStringList arguments;
    
        arguments << "0" << QString::number(wps.front().x()) << QString::number(wps.front().y()) << "0" << QString::number(wps.back().x()) << QString::number(wps.back().y()) << "prueba_princi.bmp" << "0 0 +" ;
    
        QString folder = "/home/";
    
        QProcess *myProcess = new QProcess(this);
    
        myProcess->setWorkingDirectory(folder);
    
        myProcess->start(program,arguments);
    
    1 Reply Last reply
    0
    • SGaistS Offline
      SGaistS Offline
      SGaist
      Lifetime Qt Champion
      wrote on last edited by
      #12

      What is the full path to princi ? And what is the full path to your application ?

      Interested in AI ? www.idiap.ch
      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

      AlvaroSA 1 Reply Last reply
      0
      • SGaistS SGaist

        What is the full path to princi ? And what is the full path to your application ?

        AlvaroSA Offline
        AlvaroSA Offline
        AlvaroS
        wrote on last edited by
        #13

        @SGaist Full path of princi (which is the executable) is /home/
        and full path of my QT aplication is /home/workspace

        1 Reply Last reply
        0
        • jsulmJ Offline
          jsulmJ Offline
          jsulm
          Lifetime Qt Champion
          wrote on last edited by
          #14

          /home is not the full path to your application except it is called home and is located in the root directory.
          So, you can start the program in a shell with /home/princi?
          Did you try it?
          This is quite strange path: in /home you usually have a directory for each user and /home is not writable by normal user.

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

          AlvaroSA 1 Reply Last reply
          2
          • jsulmJ jsulm

            /home is not the full path to your application except it is called home and is located in the root directory.
            So, you can start the program in a shell with /home/princi?
            Did you try it?
            This is quite strange path: in /home you usually have a directory for each user and /home is not writable by normal user.

            AlvaroSA Offline
            AlvaroSA Offline
            AlvaroS
            wrote on last edited by
            #15

            @jsulm sorry yes, it is in /home/user1/ but it does not run as well...

            1 Reply Last reply
            0
            • mrjjM Offline
              mrjjM Offline
              mrjj
              Lifetime Qt Champion
              wrote on last edited by
              #16

              @AlvaroS said:

              QString program = "princi";

              should be

              QString program = "/home/user1/princi";

              ?

              AlvaroSA 1 Reply Last reply
              1
              • mrjjM mrjj

                @AlvaroS said:

                QString program = "princi";

                should be

                QString program = "/home/user1/princi";

                ?

                AlvaroSA Offline
                AlvaroSA Offline
                AlvaroS
                wrote on last edited by
                #17

                @mrjj It works in the same way... :(

                jsulmJ mrjjM 2 Replies Last reply
                0
                • AlvaroSA AlvaroS

                  @mrjj It works in the same way... :(

                  jsulmJ Offline
                  jsulmJ Offline
                  jsulm
                  Lifetime Qt Champion
                  wrote on last edited by
                  #18

                  @AlvaroS So, if you enter /home/user1/princi in a terminal window and press enter it does not start? What happens? Any error message?

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

                  AlvaroSA 1 Reply Last reply
                  1
                  • AlvaroSA AlvaroS

                    @mrjj It works in the same way... :(

                    mrjjM Offline
                    mrjjM Offline
                    mrjj
                    Lifetime Qt Champion
                    wrote on last edited by
                    #19

                    @AlvaroS

                    Ok, you must debug then
                    try to use
                    http://doc.qt.io/qt-5/qprocess.html#error
                    to see what it thinks.

                    AlvaroSA 1 Reply Last reply
                    2
                    • jsulmJ jsulm

                      @AlvaroS So, if you enter /home/user1/princi in a terminal window and press enter it does not start? What happens? Any error message?

                      AlvaroSA Offline
                      AlvaroSA Offline
                      AlvaroS
                      wrote on last edited by
                      #20

                      @jsulm In a terminal if I write

                      ./princi 0 747.37 427.68 0 844.37 42.54 prueba_princi.bmp 0 0 +
                      

                      in /home/user1/ directory it runs good

                      jsulmJ AlvaroSA 2 Replies Last reply
                      0
                      • AlvaroSA AlvaroS

                        @jsulm In a terminal if I write

                        ./princi 0 747.37 427.68 0 844.37 42.54 prueba_princi.bmp 0 0 +
                        

                        in /home/user1/ directory it runs good

                        jsulmJ Offline
                        jsulmJ Offline
                        jsulm
                        Lifetime Qt Champion
                        wrote on last edited by jsulm
                        #21

                        @AlvaroS Then try what @mrjj suggested

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

                        1 Reply Last reply
                        0
                        • mrjjM mrjj

                          @AlvaroS

                          Ok, you must debug then
                          try to use
                          http://doc.qt.io/qt-5/qprocess.html#error
                          to see what it thinks.

                          AlvaroSA Offline
                          AlvaroSA Offline
                          AlvaroS
                          wrote on last edited by
                          #22
                          This post is deleted!
                          mrjjM 1 Reply Last reply
                          0
                          • AlvaroSA AlvaroS

                            @jsulm In a terminal if I write

                            ./princi 0 747.37 427.68 0 844.37 42.54 prueba_princi.bmp 0 0 +
                            

                            in /home/user1/ directory it runs good

                            AlvaroSA Offline
                            AlvaroSA Offline
                            AlvaroS
                            wrote on last edited by AlvaroS
                            #23

                            @AlvaroS said:

                            @jsulm In a terminal if I write

                            ./princi 0 747.37 427.68 0 844.37 42.54 prueba_princi.bmp 0 0 +
                            

                            in /home/user1/ directory it runs good

                            @jsulm said:

                            @AlvaroS Then try what @mrjj suggested

                            okey, it gives me UnknowError.... http://doc.qt.io/qt-5/qprocess.html#ProcessError-enum

                            1 Reply Last reply
                            0
                            • AlvaroSA AlvaroS

                              This post is deleted!

                              mrjjM Offline
                              mrjjM Offline
                              mrjj
                              Lifetime Qt Champion
                              wrote on last edited by
                              #24

                              @AlvaroS

                              well you can use
                              qDebug() "qproc: " << myProcess->error();

                              and check the code in
                              http://doc.qt.io/qt-5/qprocess.html#ProcessError-enum

                              AlvaroSA 1 Reply Last reply
                              1
                              • mrjjM mrjj

                                @AlvaroS

                                well you can use
                                qDebug() "qproc: " << myProcess->error();

                                and check the code in
                                http://doc.qt.io/qt-5/qprocess.html#ProcessError-enum

                                AlvaroSA Offline
                                AlvaroSA Offline
                                AlvaroS
                                wrote on last edited by
                                #25

                                @mrjj Yes thanks!! See my last post. Thanks again. It gives me Unknow error...

                                mrjjM 1 Reply Last reply
                                0
                                • AlvaroSA AlvaroS

                                  @mrjj Yes thanks!! See my last post. Thanks again. It gives me Unknow error...

                                  mrjjM Offline
                                  mrjjM Offline
                                  mrjj
                                  Lifetime Qt Champion
                                  wrote on last edited by
                                  #26

                                  @AlvaroS

                                  " This is the default return value of error()."

                                  You do call it AFTER u call
                                  myProcess->start(program,arguments); ?

                                  AlvaroSA 1 Reply Last reply
                                  1
                                  • mrjjM mrjj

                                    @AlvaroS

                                    " This is the default return value of error()."

                                    You do call it AFTER u call
                                    myProcess->start(program,arguments); ?

                                    AlvaroSA Offline
                                    AlvaroSA Offline
                                    AlvaroS
                                    wrote on last edited by
                                    #27

                                    @mrjj Yes:

                                        myProcess->start(program, arguments);
                                    
                                        QProcess::ProcessError error = myProcess->error();
                                    
                                    mrjjM 1 Reply Last reply
                                    0
                                    • AlvaroSA AlvaroS

                                      @mrjj Yes:

                                          myProcess->start(program, arguments);
                                      
                                          QProcess::ProcessError error = myProcess->error();
                                      
                                      mrjjM Offline
                                      mrjjM Offline
                                      mrjj
                                      Lifetime Qt Champion
                                      wrote on last edited by
                                      #28

                                      @AlvaroS
                                      hmm really odd then
                                      it should say FailedToStart

                                      Just to be 100% clear.

                                      princi is never run ?

                                      AlvaroSA 1 Reply Last reply
                                      1
                                      • mrjjM mrjj

                                        @AlvaroS
                                        hmm really odd then
                                        it should say FailedToStart

                                        Just to be 100% clear.

                                        princi is never run ?

                                        AlvaroSA Offline
                                        AlvaroSA Offline
                                        AlvaroS
                                        wrote on last edited by
                                        #29

                                        @mrjj said:

                                        @AlvaroS
                                        hmm really odd then
                                        it should say FailedToStart

                                        Just to be 100% clear.

                                        princi is never run ?

                                        okey look.
                                        if I write:

                                            myProcess->start(program, arguments);
                                        
                                            myProcess->waitForFinished(3000);
                                        
                                            QProcess::ProcessError error = myProcess->error();
                                        
                                        

                                        Now error says:
                                        QProcess::Crashed The process crashed some time after starting successfully.

                                        1 Reply Last reply
                                        0
                                        • mrjjM Offline
                                          mrjjM Offline
                                          mrjj
                                          Lifetime Qt Champion
                                          wrote on last edited by mrjj
                                          #30

                                          so it sounds like your princi do run but it crashes?

                                          oh. sorry my bad. start is async so calling error right after was
                                          not correct.

                                          waitForFinished fixed that.

                                          AlvaroSA 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