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Forum Update on Monday, May 27th 2025

QT posix message queue

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  • J Offline
    J Offline
    jish
    wrote on 19 May 2017, 04:55 last edited by
    #1

    HI i'm new to QT.
    I have one application sending data packets to message queue. And my second application is QT. i have to receive that data from qt. How can i use posix message queue commands in qt??(like mq_receive). Please help.

    J 1 Reply Last reply 19 May 2017, 06:06
    0
    • J jish
      19 May 2017, 04:55

      HI i'm new to QT.
      I have one application sending data packets to message queue. And my second application is QT. i have to receive that data from qt. How can i use posix message queue commands in qt??(like mq_receive). Please help.

      J Offline
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      jsulm
      Lifetime Qt Champion
      wrote on 19 May 2017, 06:06 last edited by
      #2

      @jish This is not related to Qt.
      You use message queues in your Qt app as in any other C/C++ app.
      Qt is a C++ framework, so you can use C APIs directly.
      So you simply do it like in your first app.

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

      1 Reply Last reply
      0
      • J Offline
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        jish
        wrote on 19 May 2017, 06:08 last edited by jish
        #3

        @jsulm so no need to use header files specific to qt? mqueue.h is not working with qt.

        J 2 Replies Last reply 19 May 2017, 06:10
        0
        • J jish
          19 May 2017, 06:08

          @jsulm so no need to use header files specific to qt? mqueue.h is not working with qt.

          J Offline
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          jsulm
          Lifetime Qt Champion
          wrote on 19 May 2017, 06:10 last edited by
          #4

          @jish Sorry, but how is it related to Qt? You need Qt header files if you use Qt. If I understood you correctly your second app uses Qt, so you need to include needed Qt header files - it doesn't matter whether this app uses message queues or not.

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

          1 Reply Last reply
          0
          • J jish
            19 May 2017, 06:08

            @jsulm so no need to use header files specific to qt? mqueue.h is not working with qt.

            J Offline
            J Offline
            jsulm
            Lifetime Qt Champion
            wrote on 19 May 2017, 06:10 last edited by jsulm
            #5

            @jish "mqueue.h is not working with qt" - why? What happens? Qt is not a programming language...

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

            J 1 Reply Last reply 19 May 2017, 06:18
            0
            • J jsulm
              19 May 2017, 06:10

              @jish "mqueue.h is not working with qt" - why? What happens? Qt is not a programming language...

              J Offline
              J Offline
              jish
              wrote on 19 May 2017, 06:18 last edited by
              #6

              @jsulm for using mq_send/mq_receive i need to add mqueue.h to my QT program. But it shows no such file or directory

              J 1 Reply Last reply 19 May 2017, 06:27
              0
              • J jish
                19 May 2017, 06:18

                @jsulm for using mq_send/mq_receive i need to add mqueue.h to my QT program. But it shows no such file or directory

                J Offline
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                jsulm
                Lifetime Qt Champion
                wrote on 19 May 2017, 06:27 last edited by jsulm
                #7

                @jish Can you show how you're doing this? Did you check that you have mqueue.h ?
                "But it shows no such file or directory" - who shows this? Is it an error during compiling? Is it shown in QtCreator?

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

                J 1 Reply Last reply 19 May 2017, 06:39
                0
                • J jsulm
                  19 May 2017, 06:27

                  @jish Can you show how you're doing this? Did you check that you have mqueue.h ?
                  "But it shows no such file or directory" - who shows this? Is it an error during compiling? Is it shown in QtCreator?

                  J Offline
                  J Offline
                  jish
                  wrote on 19 May 2017, 06:39 last edited by
                  #8

                  @jsulm yes..it is an error during compilation in qtcreator

                  J 1 Reply Last reply 19 May 2017, 06:40
                  0
                  • J jish
                    19 May 2017, 06:39

                    @jsulm yes..it is an error during compilation in qtcreator

                    J Offline
                    J Offline
                    jsulm
                    Lifetime Qt Champion
                    wrote on 19 May 2017, 06:40 last edited by jsulm
                    #9

                    @jish Do you have this header file in your system?
                    And can you show how you include it in your code?

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

                    J 1 Reply Last reply 19 May 2017, 06:46
                    0
                    • J jsulm
                      19 May 2017, 06:40

                      @jish Do you have this header file in your system?
                      And can you show how you include it in your code?

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                      jish
                      wrote on 19 May 2017, 06:46 last edited by
                      #10

                      @jsulm #include "mainwindow.h"
                      #include "ui_mainwindow.h"
                      #include <Mqueue.h>
                      MainWindow::MainWindow(QWidget *parent) :
                      QMainWindow(parent),
                      ui(new Ui::MainWindow)
                      {
                      ui->setupUi(this);
                      mqd_t mqid;
                      mqid=mq_open("/hmi_chnl_ic",O_RDONLY);
                      if(mqid==-1)
                      {
                      QDebug()<<"error opening message queue";
                      }
                      }
                      this is the sample code..please forgive me if i'm asking anything stupid.And please do tell me where do ineed to add mqueue.h to get that in my program.

                      J 1 Reply Last reply 19 May 2017, 06:47
                      0
                      • J jish
                        19 May 2017, 06:46

                        @jsulm #include "mainwindow.h"
                        #include "ui_mainwindow.h"
                        #include <Mqueue.h>
                        MainWindow::MainWindow(QWidget *parent) :
                        QMainWindow(parent),
                        ui(new Ui::MainWindow)
                        {
                        ui->setupUi(this);
                        mqd_t mqid;
                        mqid=mq_open("/hmi_chnl_ic",O_RDONLY);
                        if(mqid==-1)
                        {
                        QDebug()<<"error opening message queue";
                        }
                        }
                        this is the sample code..please forgive me if i'm asking anything stupid.And please do tell me where do ineed to add mqueue.h to get that in my program.

                        J Offline
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                        jsulm
                        Lifetime Qt Champion
                        wrote on 19 May 2017, 06:47 last edited by
                        #11

                        @jish said in QT posix message queue:

                        #include <Mqueue.h>

                        it must be

                        #include <mqueue.h>
                        

                        You need to include it where you want to use it. Where it is depends on your design.

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

                        J 1 Reply Last reply 19 May 2017, 06:53
                        0
                        • J jsulm
                          19 May 2017, 06:47

                          @jish said in QT posix message queue:

                          #include <Mqueue.h>

                          it must be

                          #include <mqueue.h>
                          

                          You need to include it where you want to use it. Where it is depends on your design.

                          J Offline
                          J Offline
                          jish
                          wrote on 19 May 2017, 06:53 last edited by jish
                          #12

                          @jsulm mqueue.h is also not working..
                          You need to include it where you want to use it??? i tried to include it with the headers in .pro file..but no use.

                          J 1 Reply Last reply 19 May 2017, 06:59
                          0
                          • J jish
                            19 May 2017, 06:53

                            @jsulm mqueue.h is also not working..
                            You need to include it where you want to use it??? i tried to include it with the headers in .pro file..but no use.

                            J Offline
                            J Offline
                            jsulm
                            Lifetime Qt Champion
                            wrote on 19 May 2017, 06:59 last edited by
                            #13

                            @jish "mqueue.h is also not working" - if you say something is not working you should always say what exactly is not working...
                            I already asked you two times whether you have this header file in your system. Can you please answer this question?

                            "You need to include it where you want to use it???" - before you asked "And please do tell me where do ineed to add mqueue.h to get that in my program". Maybe I misunderstood your question. You do not need to add this header file to your project. You just use it - system headers files are never added to the project directly.
                            "i tried to include it with the headers in .pro file..but no use" - this is not needed! mqueue.h is usually already installed in your system (I guess you're using Linux?).
                            This simple program should compile:

                            #include "mqueue.h"
                            
                            int main(void)
                            {
                                return 0;
                            }
                            

                            Does it compile if you do it like this:

                            g++ -o test_mqueue test_mqueue.cpp
                            

                            ?

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

                            J 1 Reply Last reply 19 May 2017, 07:04
                            1
                            • J jsulm
                              19 May 2017, 06:59

                              @jish "mqueue.h is also not working" - if you say something is not working you should always say what exactly is not working...
                              I already asked you two times whether you have this header file in your system. Can you please answer this question?

                              "You need to include it where you want to use it???" - before you asked "And please do tell me where do ineed to add mqueue.h to get that in my program". Maybe I misunderstood your question. You do not need to add this header file to your project. You just use it - system headers files are never added to the project directly.
                              "i tried to include it with the headers in .pro file..but no use" - this is not needed! mqueue.h is usually already installed in your system (I guess you're using Linux?).
                              This simple program should compile:

                              #include "mqueue.h"
                              
                              int main(void)
                              {
                                  return 0;
                              }
                              

                              Does it compile if you do it like this:

                              g++ -o test_mqueue test_mqueue.cpp
                              

                              ?

                              J Offline
                              J Offline
                              jish
                              wrote on 19 May 2017, 07:04 last edited by jish
                              #14

                              @jsulm no idont have this header file in my system.That is why i'm asking where do add this header.

                              mrjjM J 2 Replies Last reply 19 May 2017, 07:06
                              0
                              • J jish
                                19 May 2017, 07:04

                                @jsulm no idont have this header file in my system.That is why i'm asking where do add this header.

                                mrjjM Offline
                                mrjjM Offline
                                mrjj
                                Lifetime Qt Champion
                                wrote on 19 May 2017, 07:06 last edited by
                                #15

                                @jish
                                Its a linux header. Not related to Qt at all. This is where it is on my system

                                alt text

                                1 Reply Last reply
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                                • J jish
                                  19 May 2017, 07:04

                                  @jsulm no idont have this header file in my system.That is why i'm asking where do add this header.

                                  J Offline
                                  J Offline
                                  jsulm
                                  Lifetime Qt Champion
                                  wrote on 19 May 2017, 07:06 last edited by
                                  #16

                                  @jish Do you use a Linux distribution?
                                  If so then install needed package. On Ubuntu you need to install libc6-dev package.

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

                                  J 1 Reply Last reply 19 May 2017, 07:11
                                  2
                                  • J jsulm
                                    19 May 2017, 07:06

                                    @jish Do you use a Linux distribution?
                                    If so then install needed package. On Ubuntu you need to install libc6-dev package.

                                    J Offline
                                    J Offline
                                    jish
                                    wrote on 19 May 2017, 07:11 last edited by jish
                                    #17

                                    @jsulm i'm using linux distribution.
                                    i am able to use mqueue.h in my linux program without any error. Only using with qt showed the error message.

                                    J 1 Reply Last reply 19 May 2017, 07:12
                                    0
                                    • J jish
                                      19 May 2017, 07:11

                                      @jsulm i'm using linux distribution.
                                      i am able to use mqueue.h in my linux program without any error. Only using with qt showed the error message.

                                      J Offline
                                      J Offline
                                      jsulm
                                      Lifetime Qt Champion
                                      wrote on 19 May 2017, 07:12 last edited by
                                      #18

                                      @jish It would be helpful to know which one.
                                      What does

                                      find /usr -name mqueue.h
                                      

                                      output?

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

                                      J 1 Reply Last reply 19 May 2017, 07:16
                                      0
                                      • J jsulm
                                        19 May 2017, 07:12

                                        @jish It would be helpful to know which one.
                                        What does

                                        find /usr -name mqueue.h
                                        

                                        output?

                                        J Offline
                                        J Offline
                                        jish
                                        wrote on 19 May 2017, 07:16 last edited by
                                        #19

                                        @jsulm said in QT posix message queue:

                                        find /usr -name mqueue.h

                                        output
                                        /usr/include/mqueue.h
                                        /usr/include/x86_64-linux-gnu/bits/mqueue.h
                                        /usr/include/linux/mqueue.h
                                        /usr/src/linux-headers-3.13.0-24-generic/include/config/posix/mqueue.h
                                        /usr/src/linux-headers-3.13.0-117/include/uapi/linux/mqueue.h
                                        /usr/src/linux-headers-3.13.0-117-generic/include/config/posix/mqueue.h
                                        /usr/src/linux-headers-3.13.0-24/include/uapi/linux/mqueue.h

                                        J 2 Replies Last reply 19 May 2017, 07:19
                                        0
                                        • J jish
                                          19 May 2017, 07:16

                                          @jsulm said in QT posix message queue:

                                          find /usr -name mqueue.h

                                          output
                                          /usr/include/mqueue.h
                                          /usr/include/x86_64-linux-gnu/bits/mqueue.h
                                          /usr/include/linux/mqueue.h
                                          /usr/src/linux-headers-3.13.0-24-generic/include/config/posix/mqueue.h
                                          /usr/src/linux-headers-3.13.0-117/include/uapi/linux/mqueue.h
                                          /usr/src/linux-headers-3.13.0-117-generic/include/config/posix/mqueue.h
                                          /usr/src/linux-headers-3.13.0-24/include/uapi/linux/mqueue.h

                                          J Offline
                                          J Offline
                                          jsulm
                                          Lifetime Qt Champion
                                          wrote on 19 May 2017, 07:19 last edited by
                                          #20

                                          @jish What is the error message after changing

                                          #include <Mqueue.h>
                                          

                                          to

                                          #include <mqueue.h>
                                          

                                          ?

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

                                          J 1 Reply Last reply 19 May 2017, 07:24
                                          0

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