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embed a python function into my Qt App.

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  • V vinaygopal

    When i click a button, i want to open up the python script (.py file) and run the python script written by me and exit python. I should be able to pass arguments to the python file through Qt c++? please help me out on how to achieve this. i did do some reading about QProcess class but i am not able to achieve this.

    jsulmJ Offline
    jsulmJ Offline
    jsulm
    Lifetime Qt Champion
    wrote on last edited by
    #2

    @vinaygopal Take a look at https://docs.python.org/2/extending/embedding.html No need for QProcess I think.

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

    V 1 Reply Last reply
    5
    • V vinaygopal

      When i click a button, i want to open up the python script (.py file) and run the python script written by me and exit python. I should be able to pass arguments to the python file through Qt c++? please help me out on how to achieve this. i did do some reading about QProcess class but i am not able to achieve this.

      JonBJ Offline
      JonBJ Offline
      JonB
      wrote on last edited by JonB
      #3

      @vinaygopal
      You can indeed go down @jsulm's path, but embedding is a lot more involved than just running a subprocess. Which one you need depends on what this script is trying to do/what you want to achieve.

      If you want to pass arguments in/receive arguments back then in-process Python embedding may indeed be best. But as phrased if all you want to do is run an external script with some command-line arguments just like any other OS command but it happens to be written in Python, it really is simple to do with QProcess, should take one minute to write.

      i did do some reading about QProcess class but i am not able to achieve this.

      If you wish to pursue this route, what does this mean? Show some code, it's dead easy. For example, the simplest might be a one-liner using https://doc.qt.io/qt-5/qprocess.html#execute:

      int result = QProcess::execute("python", QStringList() << arg1 << arg2);
      
      
      1 Reply Last reply
      5
      • jsulmJ jsulm

        @vinaygopal Take a look at https://docs.python.org/2/extending/embedding.html No need for QProcess I think.

        V Offline
        V Offline
        vinaygopal
        wrote on last edited by vinaygopal
        #4

        @jsulm i have to include the python library files in order to include Python.h can you please tell me how to specify lib path in QT in order for me to achieve this?

        i am following this tutorial (https://www.codeproject.com/Articles/820116/Embedding-Python-program-in-a-C-Cplusplus-code) now i can include the .h file but linking it with the library i am having some problems as i do not know how to specify the library path as per the tutorial or if you know anyother way this can be achieved please let me know.

        jsulmJ 1 Reply Last reply
        0
        • V vinaygopal

          @jsulm i have to include the python library files in order to include Python.h can you please tell me how to specify lib path in QT in order for me to achieve this?

          i am following this tutorial (https://www.codeproject.com/Articles/820116/Embedding-Python-program-in-a-C-Cplusplus-code) now i can include the .h file but linking it with the library i am having some problems as i do not know how to specify the library path as per the tutorial or if you know anyother way this can be achieved please let me know.

          jsulmJ Offline
          jsulmJ Offline
          jsulm
          Lifetime Qt Champion
          wrote on last edited by
          #5

          @vinaygopal Please take a look at https://doc.qt.io/qt-5/qmake-variable-reference.html#libs

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

          V 1 Reply Last reply
          2
          • jsulmJ jsulm

            @vinaygopal Please take a look at https://doc.qt.io/qt-5/qmake-variable-reference.html#libs

            V Offline
            V Offline
            vinaygopal
            wrote on last edited by
            #6

            @jsulm i have done the changes

            INCLUDEPATH +="C:\Users\vinay\AppData\Local\Programs\Python\Python37-32\include"
            
            wind32:LIBS += C:/Users/vinay/AppData/Local/Programs/Python/Python37-32/libs
            
            
            
            

            i have done the changes as per the document my include file works that is python.h is found but it is not able to link to the library as the path specified in the LIBS is a the directory to a bunch of libraries in python. i get this warning at the top of the screen

            "the code model could not parse an input file,which might lead to incorrect code completion"

            jsulmJ 1 Reply Last reply
            0
            • V vinaygopal

              @jsulm i have done the changes

              INCLUDEPATH +="C:\Users\vinay\AppData\Local\Programs\Python\Python37-32\include"
              
              wind32:LIBS += C:/Users/vinay/AppData/Local/Programs/Python/Python37-32/libs
              
              
              
              

              i have done the changes as per the document my include file works that is python.h is found but it is not able to link to the library as the path specified in the LIBS is a the directory to a bunch of libraries in python. i get this warning at the top of the screen

              "the code model could not parse an input file,which might lead to incorrect code completion"

              jsulmJ Offline
              jsulmJ Offline
              jsulm
              Lifetime Qt Champion
              wrote on last edited by
              #7

              @vinaygopal said in embed a python function into my Qt App.:

              "the code model could not parse an input file,which might lead to incorrect code completion"

              You can ignore this.

              Can you show the exact linker error?

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

              V 2 Replies Last reply
              1
              • jsulmJ jsulm

                @vinaygopal said in embed a python function into my Qt App.:

                "the code model could not parse an input file,which might lead to incorrect code completion"

                You can ignore this.

                Can you show the exact linker error?

                V Offline
                V Offline
                vinaygopal
                wrote on last edited by
                #8
                This post is deleted!
                1 Reply Last reply
                0
                • jsulmJ jsulm

                  @vinaygopal said in embed a python function into my Qt App.:

                  "the code model could not parse an input file,which might lead to incorrect code completion"

                  You can ignore this.

                  Can you show the exact linker error?

                  V Offline
                  V Offline
                  vinaygopal
                  wrote on last edited by
                  #9

                  @jsulm these are the errors i get

                  this is my main fail

                  #include <QApplication>
                  #include <QDebug>
                  #include <Python.h>
                  
                  
                  
                  int main(int argc, char *argv[])
                  {
                      QApplication a(argc, argv);
                      qDebug()<<"working"<<endl;
                  
                  
                      return a.exec();
                  

                  these are the errors

                  C:\Users\vinay\AppData\Local\Programs\Python\Python37-32\include\pytime.h:6: In file included from ..\..\..\AppData\Local\Programs\Python\Python37-32\include/pytime.h:6:0,
                  
                  C:\Users\vinay\AppData\Local\Programs\Python\Python37-32\include\Python.h:87: from ..\..\..\AppData\Local\Programs\Python\Python37-32\include/Python.h:87,
                  
                  C:\Users\vinay\Documents\first_qml_training\example_project\main.cpp:6: from ..\example_project\main.cpp:6:
                  
                  C:\Users\vinay\AppData\Local\Programs\Python\Python37-32\include\object.h:448: error: expected unqualified-id before ';' token
                       PyType_Slot *slots; /* terminated by slot==0. */
                  
                                     ^
                  
                  jsulmJ 1 Reply Last reply
                  0
                  • V vinaygopal

                    @jsulm these are the errors i get

                    this is my main fail

                    #include <QApplication>
                    #include <QDebug>
                    #include <Python.h>
                    
                    
                    
                    int main(int argc, char *argv[])
                    {
                        QApplication a(argc, argv);
                        qDebug()<<"working"<<endl;
                    
                    
                        return a.exec();
                    

                    these are the errors

                    C:\Users\vinay\AppData\Local\Programs\Python\Python37-32\include\pytime.h:6: In file included from ..\..\..\AppData\Local\Programs\Python\Python37-32\include/pytime.h:6:0,
                    
                    C:\Users\vinay\AppData\Local\Programs\Python\Python37-32\include\Python.h:87: from ..\..\..\AppData\Local\Programs\Python\Python37-32\include/Python.h:87,
                    
                    C:\Users\vinay\Documents\first_qml_training\example_project\main.cpp:6: from ..\example_project\main.cpp:6:
                    
                    C:\Users\vinay\AppData\Local\Programs\Python\Python37-32\include\object.h:448: error: expected unqualified-id before ';' token
                         PyType_Slot *slots; /* terminated by slot==0. */
                    
                                       ^
                    
                    jsulmJ Offline
                    jsulmJ Offline
                    jsulm
                    Lifetime Qt Champion
                    wrote on last edited by
                    #10

                    @vinaygopal This is not linker error but compiler.
                    Try to include the header like this:

                    extern "C"
                    {
                      #include <Python.h>
                    }
                    

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

                    V 1 Reply Last reply
                    1
                    • jsulmJ jsulm

                      @vinaygopal This is not linker error but compiler.
                      Try to include the header like this:

                      extern "C"
                      {
                        #include <Python.h>
                      }
                      
                      V Offline
                      V Offline
                      vinaygopal
                      wrote on last edited by
                      #11

                      @jsulm I tried it and i got the same set of errors however when i tried with the right click and add library method i get this following error

                      :-1: error: No rule to make target 'C:/Users/vinay/Documents/first_qml_training/example_project/../../../AppData/Local/Programs/Python/Python37-32/libs/libpython37d.a', needed by 'debug/example_project.exe'.  Stop.
                      
                      jsulmJ 1 Reply Last reply
                      0
                      • V vinaygopal

                        @jsulm I tried it and i got the same set of errors however when i tried with the right click and add library method i get this following error

                        :-1: error: No rule to make target 'C:/Users/vinay/Documents/first_qml_training/example_project/../../../AppData/Local/Programs/Python/Python37-32/libs/libpython37d.a', needed by 'debug/example_project.exe'.  Stop.
                        
                        jsulmJ Offline
                        jsulmJ Offline
                        jsulm
                        Lifetime Qt Champion
                        wrote on last edited by
                        #12

                        @vinaygopal Can you show your pro file?

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

                        V 1 Reply Last reply
                        1
                        • jsulmJ jsulm

                          @vinaygopal Can you show your pro file?

                          V Offline
                          V Offline
                          vinaygopal
                          wrote on last edited by
                          #13

                          @jsulm

                          QT       += core gui networkauth
                          
                          greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
                          
                          TARGET = example_project
                          TEMPLATE = app
                          
                          
                          # The following define makes your compiler emit warnings if you use
                          # any feature of Qt which has been marked as deprecated (the exact warnings
                          # depend on your compiler). Please consult the documentation of the
                          # deprecated API in order to know how to port your code away from it.
                          DEFINES += QT_DEPRECATED_WARNINGS
                          
                          # You can also make your code fail to compile if you use deprecated APIs.
                          # In order to do so, uncomment the following line.
                          # You can also select to disable deprecated APIs only up to a certain version of Qt.
                          #DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0
                          
                          CONFIG += c++11
                          
                          SOURCES += \
                                  main.cpp \
                                  google_widget.cpp
                          
                          HEADERS += \
                                  google_widget.h
                          
                          FORMS += \
                                  google_widget.ui
                          
                          # Default rules for deployment.
                          qnx: target.path = /tmp/$${TARGET}/bin
                          else: unix:!android: target.path = /opt/$${TARGET}/bin
                          !isEmpty(target.path): INSTALLS += target
                          
                          DISTFILES += \
                              upload_to_cloud.py
                          
                          
                          #CONFIG += no_lflags_merge
                          
                          INCLUDEPATH +="C:\Users\vinay\AppData\Local\Programs\Python\Python37-32\include"
                          
                          
                          
                          win32:CONFIG(release, debug|release): LIBS += -L$$PWD/../../../AppData/Local/Programs/Python/Python37-32/libs/ -lpython37
                          else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/../../../AppData/Local/Programs/Python/Python37-32/libs/ -lpython37d
                          else:unix: LIBS += -L$$PWD/../../../AppData/Local/Programs/Python/Python37-32/libs/ -lpython37
                          
                          
                          win32-g++:CONFIG(release, debug|release): PRE_TARGETDEPS += $$PWD/../../../AppData/Local/Programs/Python/Python37-32/libs/libpython37.a
                          else:win32-g++:CONFIG(debug, debug|release): PRE_TARGETDEPS += $$PWD/../../../AppData/Local/Programs/Python/Python37-32/libs/libpython37d.a
                          else:win32:!win32-g++:CONFIG(release, debug|release): PRE_TARGETDEPS += $$PWD/../../../AppData/Local/Programs/Python/Python37-32/libs/python37.lib
                          else:win32:!win32-g++:CONFIG(debug, debug|release): PRE_TARGETDEPS += $$PWD/../../../AppData/Local/Programs/Python/Python37-32/libs/python37d.lib
                          else:unix: PRE_TARGETDEPS += $$PWD/../../../AppData/Local/Programs/Python/Python37-32/libs/libpython37.a
                          
                          
                          jsulmJ 1 Reply Last reply
                          0
                          • V vinaygopal

                            @jsulm

                            QT       += core gui networkauth
                            
                            greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
                            
                            TARGET = example_project
                            TEMPLATE = app
                            
                            
                            # The following define makes your compiler emit warnings if you use
                            # any feature of Qt which has been marked as deprecated (the exact warnings
                            # depend on your compiler). Please consult the documentation of the
                            # deprecated API in order to know how to port your code away from it.
                            DEFINES += QT_DEPRECATED_WARNINGS
                            
                            # You can also make your code fail to compile if you use deprecated APIs.
                            # In order to do so, uncomment the following line.
                            # You can also select to disable deprecated APIs only up to a certain version of Qt.
                            #DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0
                            
                            CONFIG += c++11
                            
                            SOURCES += \
                                    main.cpp \
                                    google_widget.cpp
                            
                            HEADERS += \
                                    google_widget.h
                            
                            FORMS += \
                                    google_widget.ui
                            
                            # Default rules for deployment.
                            qnx: target.path = /tmp/$${TARGET}/bin
                            else: unix:!android: target.path = /opt/$${TARGET}/bin
                            !isEmpty(target.path): INSTALLS += target
                            
                            DISTFILES += \
                                upload_to_cloud.py
                            
                            
                            #CONFIG += no_lflags_merge
                            
                            INCLUDEPATH +="C:\Users\vinay\AppData\Local\Programs\Python\Python37-32\include"
                            
                            
                            
                            win32:CONFIG(release, debug|release): LIBS += -L$$PWD/../../../AppData/Local/Programs/Python/Python37-32/libs/ -lpython37
                            else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/../../../AppData/Local/Programs/Python/Python37-32/libs/ -lpython37d
                            else:unix: LIBS += -L$$PWD/../../../AppData/Local/Programs/Python/Python37-32/libs/ -lpython37
                            
                            
                            win32-g++:CONFIG(release, debug|release): PRE_TARGETDEPS += $$PWD/../../../AppData/Local/Programs/Python/Python37-32/libs/libpython37.a
                            else:win32-g++:CONFIG(debug, debug|release): PRE_TARGETDEPS += $$PWD/../../../AppData/Local/Programs/Python/Python37-32/libs/libpython37d.a
                            else:win32:!win32-g++:CONFIG(release, debug|release): PRE_TARGETDEPS += $$PWD/../../../AppData/Local/Programs/Python/Python37-32/libs/python37.lib
                            else:win32:!win32-g++:CONFIG(debug, debug|release): PRE_TARGETDEPS += $$PWD/../../../AppData/Local/Programs/Python/Python37-32/libs/python37d.lib
                            else:unix: PRE_TARGETDEPS += $$PWD/../../../AppData/Local/Programs/Python/Python37-32/libs/libpython37.a
                            
                            
                            jsulmJ Offline
                            jsulmJ Offline
                            jsulm
                            Lifetime Qt Champion
                            wrote on last edited by
                            #14

                            @vinaygopal On Windows it should be:

                            LIBS += $$PWD/../../../AppData/Local/Programs/Python/Python37-32/libs/python37.lib
                            

                            See https://doc.qt.io/qt-5/qmake-variable-reference.html#libs

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

                            V 1 Reply Last reply
                            2
                            • jsulmJ jsulm

                              @vinaygopal On Windows it should be:

                              LIBS += $$PWD/../../../AppData/Local/Programs/Python/Python37-32/libs/python37.lib
                              

                              See https://doc.qt.io/qt-5/qmake-variable-reference.html#libs

                              V Offline
                              V Offline
                              vinaygopal
                              wrote on last edited by
                              #15

                              @jsulm i did add the library as you had recomended it still did'nt work and more importantly i figured the module python.h and its equivalent library is not compatible with mingw gcc compiler it is only compatible with microsoft specific compilers as suggested by this question (https://stackoverflow.com/questions/6731100/link-to-python-with-mingw) they have provided an answer but is there a simpler way to get this done?

                              jsulmJ 1 Reply Last reply
                              0
                              • V vinaygopal

                                @jsulm i did add the library as you had recomended it still did'nt work and more importantly i figured the module python.h and its equivalent library is not compatible with mingw gcc compiler it is only compatible with microsoft specific compilers as suggested by this question (https://stackoverflow.com/questions/6731100/link-to-python-with-mingw) they have provided an answer but is there a simpler way to get this done?

                                jsulmJ Offline
                                jsulmJ Offline
                                jsulm
                                Lifetime Qt Champion
                                wrote on last edited by
                                #16

                                @vinaygopal One question: do you build your app as 64bit? Your Python seems to be 32bit.

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

                                V 1 Reply Last reply
                                0
                                • jsulmJ jsulm

                                  @vinaygopal One question: do you build your app as 64bit? Your Python seems to be 32bit.

                                  V Offline
                                  V Offline
                                  vinaygopal
                                  wrote on last edited by
                                  #17

                                  @jsulm i am building my apps in the 64 bit configuration. shoudl i change it to 32 bit and try building the program again?

                                  jsulmJ 1 Reply Last reply
                                  0
                                  • V vinaygopal

                                    @jsulm i am building my apps in the 64 bit configuration. shoudl i change it to 32 bit and try building the program again?

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

                                    @vinaygopal said in embed a python function into my Qt App.:

                                    shoudl i change it to 32 bit

                                    Yes, you can't mix 32bit and 64bit

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

                                    V 1 Reply Last reply
                                    0
                                    • jsulmJ jsulm

                                      @vinaygopal said in embed a python function into my Qt App.:

                                      shoudl i change it to 32 bit

                                      Yes, you can't mix 32bit and 64bit

                                      V Offline
                                      V Offline
                                      vinaygopal
                                      wrote on last edited by
                                      #19

                                      @jsulm uninstalled python 32 bit and reinstalled 64bit version of python and included the libraries still the same error

                                      :-1: error: No rule to make target 'C:/Users/vinay/Documents/first_qml_training/example_project/../../../AppData/Local/Programs/Python/Python38/libs/libpython38d.a', needed by 'debug/example_project.exe'. Stop.

                                      jsulmJ 1 Reply Last reply
                                      0
                                      • V vinaygopal

                                        @jsulm uninstalled python 32 bit and reinstalled 64bit version of python and included the libraries still the same error

                                        :-1: error: No rule to make target 'C:/Users/vinay/Documents/first_qml_training/example_project/../../../AppData/Local/Programs/Python/Python38/libs/libpython38d.a', needed by 'debug/example_project.exe'. Stop.

                                        jsulmJ Offline
                                        jsulmJ Offline
                                        jsulm
                                        Lifetime Qt Champion
                                        wrote on last edited by
                                        #20

                                        @vinaygopal Can you show your current pro file?
                                        Also did you a clean rebuild?

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

                                        V 1 Reply Last reply
                                        0
                                        • jsulmJ jsulm

                                          @vinaygopal Can you show your current pro file?
                                          Also did you a clean rebuild?

                                          V Offline
                                          V Offline
                                          vinaygopal
                                          wrote on last edited by
                                          #21

                                          @jsulm yes i clean the build run qmake and then build the file everytime i change the pro file

                                          #-------------------------------------------------
                                          #
                                          # Project created by QtCreator 2019-11-21T10:31:03
                                          #
                                          #-------------------------------------------------
                                          
                                          QT       += core gui networkauth
                                          
                                          greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
                                          
                                          TARGET = example_project
                                          TEMPLATE = app
                                          
                                          
                                          # The following define makes your compiler emit warnings if you use
                                          # any feature of Qt which has been marked as deprecated (the exact warnings
                                          # depend on your compiler). Please consult the documentation of the
                                          # deprecated API in order to know how to port your code away from it.
                                          DEFINES += QT_DEPRECATED_WARNINGS
                                          
                                          # You can also make your code fail to compile if you use deprecated APIs.
                                          # In order to do so, uncomment the following line.
                                          # You can also select to disable deprecated APIs only up to a certain version of Qt.
                                          #DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0
                                          
                                          CONFIG += c++11
                                          
                                          SOURCES += \
                                                  main.cpp \
                                                  google_widget.cpp
                                          
                                          HEADERS += \
                                                  google_widget.h
                                          
                                          FORMS += \
                                                  google_widget.ui
                                          
                                          # Default rules for deployment.
                                          qnx: target.path = /tmp/$${TARGET}/bin
                                          else: unix:!android: target.path = /opt/$${TARGET}/bin
                                          !isEmpty(target.path): INSTALLS += target
                                          
                                          DISTFILES += \
                                              upload_to_cloud.py
                                          
                                          
                                          #CONFIG += no_lflags_merge
                                          
                                          INCLUDEPATH="C:/Users/vinay/AppData/Local/Programs/Python/Python38/include"
                                          LIBS += $$PWD/../../../AppData/Local/Programs/Python/Python38/libs/python38.lib
                                          
                                          jsulmJ 1 Reply Last reply
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