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Looking for good explanation of creation process of Static Lib and it's Test App

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  • SGaistS Offline
    SGaistS Offline
    SGaist
    Lifetime Qt Champion
    wrote on last edited by
    #9

    Then your library is not build statically and you are not properly exporting symbols.

    For that second part see here.

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

    sitesvS 1 Reply Last reply
    3
    • SGaistS SGaist

      Then your library is not build statically and you are not properly exporting symbols.

      For that second part see here.

      sitesvS Offline
      sitesvS Offline
      sitesv
      wrote on last edited by
      #10

      @SGaist thanks. I will recode my lib.

      I there any way to debug dynamic/static lib?

      1 Reply Last reply
      0
      • SGaistS Offline
        SGaistS Offline
        SGaist
        Lifetime Qt Champion
        wrote on last edited by
        #11

        Sure, use a debug build of your library.

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

        sitesvS 1 Reply Last reply
        2
        • SGaistS SGaist

          Sure, use a debug build of your library.

          sitesvS Offline
          sitesvS Offline
          sitesv
          wrote on last edited by
          #12

          @SGaist ones more Q:
          But how the same project works in Linux?

          1 Reply Last reply
          0
          • SGaistS Offline
            SGaistS Offline
            SGaist
            Lifetime Qt Champion
            wrote on last edited by
            #13

            Because the symbol exportation does not work the same on Linux.

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

            1 Reply Last reply
            2
            • gde23G Offline
              gde23G Offline
              gde23
              wrote on last edited by
              #14

              When you have a library under windows you need to explicitly export the symbols.
              On linux it is not necessary because the symbols are managed in another way.

              Typically this is done using a preprocessor define that you add at any function / class that you wanna export like (just look it up on stackoverflow)

              #ifdef WIN32
                  #define DECL_EXPORT __declspec(dllexport)
                  #define DECL_IMPORT __declspec(dllimport)
              #else
                  #define DECL_EXPORT
                  #define DECL_IMPORT
              #endif
              
              SGaistS 1 Reply Last reply
              0
              • gde23G gde23

                When you have a library under windows you need to explicitly export the symbols.
                On linux it is not necessary because the symbols are managed in another way.

                Typically this is done using a preprocessor define that you add at any function / class that you wanna export like (just look it up on stackoverflow)

                #ifdef WIN32
                    #define DECL_EXPORT __declspec(dllexport)
                    #define DECL_IMPORT __declspec(dllimport)
                #else
                    #define DECL_EXPORT
                    #define DECL_IMPORT
                #endif
                
                SGaistS Offline
                SGaistS Offline
                SGaist
                Lifetime Qt Champion
                wrote on last edited by
                #15

                @gde23 said in Looking for good explanation of creation process of Static Lib and it's Test App:

                When you have a library under windows you need to explicitly export the symbols.
                On linux it is not necessary because the symbols are managed in another way.

                Typically this is done using a preprocessor define that you add at any function / class that you wanna export like (just look it up on stackoverflow)

                #ifdef WIN32
                    #define DECL_EXPORT __declspec(dllexport)
                    #define DECL_IMPORT __declspec(dllimport)
                #else
                    #define DECL_EXPORT
                    #define DECL_IMPORT
                #endif
                

                That is incomplete, The macro to use depend whether you are building the library or using it. See the dedicated chapter in Qt's documentation for a clean way to handle that.

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

                gde23G 1 Reply Last reply
                1
                • sitesvS Offline
                  sitesvS Offline
                  sitesv
                  wrote on last edited by sitesv
                  #16

                  @SGaist I checked my code... It is matches to link.
                  But lib and dll files are created.

                  Should this code be in pro file:

                  CONFIG += staticlib
                  

                  ?

                  So, I have included this string to pro and as a result a lib file only.

                  Could you please see my test apps? ==> app

                  1 Reply Last reply
                  0
                  • SGaistS SGaist

                    @gde23 said in Looking for good explanation of creation process of Static Lib and it's Test App:

                    When you have a library under windows you need to explicitly export the symbols.
                    On linux it is not necessary because the symbols are managed in another way.

                    Typically this is done using a preprocessor define that you add at any function / class that you wanna export like (just look it up on stackoverflow)

                    #ifdef WIN32
                        #define DECL_EXPORT __declspec(dllexport)
                        #define DECL_IMPORT __declspec(dllimport)
                    #else
                        #define DECL_EXPORT
                        #define DECL_IMPORT
                    #endif
                    

                    That is incomplete, The macro to use depend whether you are building the library or using it. See the dedicated chapter in Qt's documentation for a clean way to handle that.

                    gde23G Offline
                    gde23G Offline
                    gde23
                    wrote on last edited by
                    #17

                    @SGaist You are right. I forgot to mention that part.
                    @sitesv The dll will be created also if you do not export the symbols. But the exe will not know about the function/class inside the dll so it will not find them.
                    Did you include the defines as in the description SGaist posted?

                    sitesvS 1 Reply Last reply
                    0
                    • gde23G gde23

                      @SGaist You are right. I forgot to mention that part.
                      @sitesv The dll will be created also if you do not export the symbols. But the exe will not know about the function/class inside the dll so it will not find them.
                      Did you include the defines as in the description SGaist posted?

                      sitesvS Offline
                      sitesvS Offline
                      sitesv
                      wrote on last edited by sitesv
                      #18

                      @gde23 said in Looking for good explanation of creation process of Static Lib and it's Test App:

                      @SGaist You are right. I forgot to mention that part.
                      @sitesv The dll will be created also if you do not export the symbols. But the exe will not know about the function/class inside the dll so it will not find them.
                      Did you include the defines as in the description SGaist posted?

                      Yes. I checked it. Could you view my code by this link?

                      UPD: I inserted the line "extern int test();" to main.cpp. And voila!

                      1 Reply Last reply
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