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Is there a "new" style for casting?

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  • JonBJ JonB

    @saber
    Although we cannot be sure, chances are that the last line of that header file should be:

    #endif
    

    to match the #ifndef started at line #17. (This is a common pattern to allow a header to be included more than once without it doing any harm.) Have a look at other header files (maybe from the same library?) and you should see this. You should fix this by adding the line --- at present the compiler/editor will be treating your file as though it did have that line at the end.

    sierdzioS Offline
    sierdzioS Offline
    sierdzio
    Moderators
    wrote on last edited by
    #35

    @JonB said in Is there a "new" style for casting?:

    at present the compiler/editor will be treating your file as though it did have that line at the end.

    Whoa, really? Which compiler allows that?

    For me (GCC) an unterminated ifdef is a hard error, compiler does not implicitly add it.

    (Z(:^

    JonBJ 1 Reply Last reply
    2
    • JonBJ JonB

      @saber
      Although we cannot be sure, chances are that the last line of that header file should be:

      #endif
      

      to match the #ifndef started at line #17. (This is a common pattern to allow a header to be included more than once without it doing any harm.) Have a look at other header files (maybe from the same library?) and you should see this. You should fix this by adding the line --- at present the compiler/editor will be treating your file as though it did have that line at the end.

      S Offline
      S Offline
      saber
      wrote on last edited by
      #36

      @JonB
      on every file "#endif " is added from first .
      all the warnings was coming up after the update of qtcreator.

      see this
      on the old version qt created this by it self

      explicit MainWindow(QWidget *parent = 0);
      

      after update
      0_1534232269589_y.png

      should i replace the 0 with nullpointer on every file??
      should it be a error in older version of compiler??
      in my qmake i add that must have c++ 11 support .

      sierdzioS 1 Reply Last reply
      0
      • S saber

        @JonB
        on every file "#endif " is added from first .
        all the warnings was coming up after the update of qtcreator.

        see this
        on the old version qt created this by it self

        explicit MainWindow(QWidget *parent = 0);
        

        after update
        0_1534232269589_y.png

        should i replace the 0 with nullpointer on every file??
        should it be a error in older version of compiler??
        in my qmake i add that must have c++ 11 support .

        sierdzioS Offline
        sierdzioS Offline
        sierdzio
        Moderators
        wrote on last edited by
        #37

        @saber said in Is there a "new" style for casting?:

        @JonB
        on every file "#endif " is added from first .
        all the warnings was coming up after the update of qtcreator.

        see this
        on the old version qt created this by it self

        explicit MainWindow(QWidget *parent = 0);
        

        after update
        0_1534232269589_y.png

        should i replace the 0 with nullpointer on every file??
        should it be a error in older version of compiler??
        in my qmake i add that must have c++ 11 support .

        These are hints from clang on how to improve your code. You are not forced to do everything it says. You are seeing them now because the clang code model is default since Qt Creator 4.7. So previously you were using the old code model which did not offer these hints. That's all there is to it. If the code compiles fine (without warnings), you can ignore the hints.

        However, it is a good idea to at least consider them, because these hints are (in 90% of cases) very good hints indeed.

        In this case yes, I'd strongly recommend using nullptr rather than zero. It is an explicit, named value that makes it harder to make a mistake.

        (Z(:^

        S 1 Reply Last reply
        4
        • VRoninV Offline
          VRoninV Offline
          VRonin
          wrote on last edited by
          #38

          I'm late to the party but just wanted to note Qt provides qFuzzyCompare and qFuzzyIsNull to compare double numbers for equality but you have to read the docs carefully before using them

          "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

          1 Reply Last reply
          2
          • sierdzioS sierdzio

            @saber said in Is there a "new" style for casting?:

            @JonB
            on every file "#endif " is added from first .
            all the warnings was coming up after the update of qtcreator.

            see this
            on the old version qt created this by it self

            explicit MainWindow(QWidget *parent = 0);
            

            after update
            0_1534232269589_y.png

            should i replace the 0 with nullpointer on every file??
            should it be a error in older version of compiler??
            in my qmake i add that must have c++ 11 support .

            These are hints from clang on how to improve your code. You are not forced to do everything it says. You are seeing them now because the clang code model is default since Qt Creator 4.7. So previously you were using the old code model which did not offer these hints. That's all there is to it. If the code compiles fine (without warnings), you can ignore the hints.

            However, it is a good idea to at least consider them, because these hints are (in 90% of cases) very good hints indeed.

            In this case yes, I'd strongly recommend using nullptr rather than zero. It is an explicit, named value that makes it harder to make a mistake.

            S Offline
            S Offline
            saber
            wrote on last edited by
            #39

            @sierdzio
            i am adding all the fix that qtcreator suggesting .

            as for the " #endif " i am ignoring it.

            aha_1980A 1 Reply Last reply
            0
            • sierdzioS sierdzio

              @JonB said in Is there a "new" style for casting?:

              at present the compiler/editor will be treating your file as though it did have that line at the end.

              Whoa, really? Which compiler allows that?

              For me (GCC) an unterminated ifdef is a hard error, compiler does not implicitly add it.

              JonBJ Online
              JonBJ Online
              JonB
              wrote on last edited by JonB
              #40

              @sierdzio said in Is there a "new" style for casting?:

              @JonB said in Is there a "new" style for casting?:

              at present the compiler/editor will be treating your file as though it did have that line at the end.

              Whoa, really? Which compiler allows that?
              For me (GCC) an unterminated ifdef is a hard error, compiler does not implicitly add it.

              The kind which generates a screenshot "Unterminated #ifdef" shown by the OP who says it's a warning but the app compiles fine.

              Now that you have said

              Ignore it, then. The code model sometimes gets bogged down in ifdefs without reason.

              I knew nothing about it being "clang". I took it that the OP had perhaps failed to get the last line of whatever he was fetching/copying (stranger things have been known to happen on this forum...). The OP should ignore my suggestion and stick with yours!

              1 Reply Last reply
              0
              • S saber

                for now i will leave as it is and inform the library author to add that enm.

                i got more warning to fix.

                0_1534231505882_aw.png

                i am getting this in all my ui based header file .
                but the app compiles fine.

                jsulmJ Offline
                jsulmJ Offline
                jsulm
                Lifetime Qt Champion
                wrote on last edited by
                #41

                @saber said in Is there a "new" style for casting?:

                add that enm

                Please don't there is NOTHING to add to the enum! Simply remove the "default" inside the switch. Please read the link I posted more carefully, it is explained there.

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

                S 1 Reply Last reply
                3
                • jsulmJ jsulm

                  @saber said in Is there a "new" style for casting?:

                  add that enm

                  Please don't there is NOTHING to add to the enum! Simply remove the "default" inside the switch. Please read the link I posted more carefully, it is explained there.

                  S Offline
                  S Offline
                  saber
                  wrote on last edited by
                  #42

                  @jsulm
                  ok.

                  1 Reply Last reply
                  0
                  • S saber

                    @sierdzio
                    i am adding all the fix that qtcreator suggesting .

                    as for the " #endif " i am ignoring it.

                    aha_1980A Offline
                    aha_1980A Offline
                    aha_1980
                    Lifetime Qt Champion
                    wrote on last edited by
                    #43

                    Hi @saber,

                    the "Unterminated conditional directive" could be either QTCREATORBUG-18801 or QTCREATORBUG-20883

                    Regards,

                    Qt has to stay free or it will die.

                    1 Reply Last reply
                    1
                    • S Offline
                      S Offline
                      saber
                      wrote on last edited by
                      #44

                      i found new issue

                      QString DiskInfo::getDiskName() const
                      {
                          QDir blocks("/sys/block");
                      
                          for (const QFileInfo entryInfo : blocks.entryInfoList(QDir::AllEntries | QDir::NoDotAndDotDot)) {
                              if (QFile::exists(QString("%1/device").arg(entryInfo.absoluteFilePath()))) {
                                  return entryInfo.baseName();
                              }
                          }
                          return QString();
                      }
                      

                      here qt telling me

                      warning: loop variable 'entryInfo' of type 'const QFileInfo' creates a copy from type 'const QFileInfo'
                      
                      A 1 Reply Last reply
                      0
                      • S saber

                        i found new issue

                        QString DiskInfo::getDiskName() const
                        {
                            QDir blocks("/sys/block");
                        
                            for (const QFileInfo entryInfo : blocks.entryInfoList(QDir::AllEntries | QDir::NoDotAndDotDot)) {
                                if (QFile::exists(QString("%1/device").arg(entryInfo.absoluteFilePath()))) {
                                    return entryInfo.baseName();
                                }
                            }
                            return QString();
                        }
                        

                        here qt telling me

                        warning: loop variable 'entryInfo' of type 'const QFileInfo' creates a copy from type 'const QFileInfo'
                        
                        A Offline
                        A Offline
                        Asperamanca
                        wrote on last edited by
                        #45

                        @saber
                        In general, when you have a new question, post in a new thread. Since this thread is marked as "solved", people may not look.

                        To your question: You loop through a list of QFileInfo objects. Your code copies the QFileInfo for every loop, which is unnecessary. Instead, you can use a const reference:

                        for (const QFileInfo& entryInfo : blocks.entryInfoList(QDir::AllEntries | QDir::NoDotAndDotDot))
                        
                        S 1 Reply Last reply
                        2
                        • A Asperamanca

                          @saber
                          In general, when you have a new question, post in a new thread. Since this thread is marked as "solved", people may not look.

                          To your question: You loop through a list of QFileInfo objects. Your code copies the QFileInfo for every loop, which is unnecessary. Instead, you can use a const reference:

                          for (const QFileInfo& entryInfo : blocks.entryInfoList(QDir::AllEntries | QDir::NoDotAndDotDot))
                          
                          S Offline
                          S Offline
                          saber
                          wrote on last edited by
                          #46

                          @Asperamanca thanks.it sloved.

                          1 Reply Last reply
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