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Boolean in C

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  • J.HilkJ J.Hilk

    @JonB said in Boolean in C:

    worked for you in gcc without you explicitly including that? Does it include it automatically or from something else

    This header was originally in the C standard library as <iso646.h>.
    Compatibility header, in C defines alternative operator representations which are keywords in C++.
    This means that in a conforming implementation, including this header has no effect.
    

    gcc has mostly a conforming implementation, at least in this regard

    JonBJ Offline
    JonBJ Offline
    JonB
    wrote on last edited by
    #24

    @J-Hilk said in Boolean in C:

    This header was originally in the C standard library as <iso646.h>.

    So what file is this in, which you say is included automatically?

    jsulmJ J.HilkJ 2 Replies Last reply
    0
    • JonBJ JonB

      @J-Hilk said in Boolean in C:

      This header was originally in the C standard library as <iso646.h>.

      So what file is this in, which you say is included automatically?

      jsulmJ Offline
      jsulmJ Offline
      jsulm
      Lifetime Qt Champion
      wrote on last edited by
      #25

      @JonB said in Boolean in C:

      which you say is included automatically?

      My understanding is that it is NOT included automatically in conforming C++ implementations because those understand these words as keywords and don't need this header file (which is only there for compatibility reasons).

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

      JonBJ 1 Reply Last reply
      2
      • JonBJ JonB

        @J-Hilk said in Boolean in C:

        This header was originally in the C standard library as <iso646.h>.

        So what file is this in, which you say is included automatically?

        J.HilkJ Offline
        J.HilkJ Offline
        J.Hilk
        Moderators
        wrote on last edited by
        #26

        @JonB I'm talking about the iso646.h @sierdzio mentioned

        https://en.cppreference.com/w/cpp/header/ciso646

        Probably the reason why MSVC doesn't have those as keywords but requires this header is, IIRC, that it doesn't have/use a dedicated c compiler for c headers and it would break legacy stuff if those were used as keywords


        Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


        Q: What's that?
        A: It's blue light.
        Q: What does it do?
        A: It turns blue.

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        • jsulmJ jsulm

          @JonB said in Boolean in C:

          which you say is included automatically?

          My understanding is that it is NOT included automatically in conforming C++ implementations because those understand these words as keywords and don't need this header file (which is only there for compatibility reasons).

          JonBJ Offline
          JonBJ Offline
          JonB
          wrote on last edited by
          #27

          @jsulm
          Mine too. But I quote from @sierdzio above:

          Last time I tried was last year. Clang, GCC all are 100% fine with it, MSVC was throwing errors.

          I now see it's supposed to be defined in some iso646.h header, I never included it, perhaps that's the reason.

          My question is (should be) aimed at him: he says it worked automatically in GCC/Clang (but not MSVC) with no #include from him, that's what I'm trying to understand.

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          • fcarneyF Offline
            fcarneyF Offline
            fcarney
            wrote on last edited by
            #28

            I know Boolean is someone's name.
            But it kind of look like a diet fad to scare people skinny: boo-lean.

            C++ is a perfectly valid school of magic.

            jsulmJ 1 Reply Last reply
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            • fcarneyF fcarney

              I know Boolean is someone's name.
              But it kind of look like a diet fad to scare people skinny: boo-lean.

              jsulmJ Offline
              jsulmJ Offline
              jsulm
              Lifetime Qt Champion
              wrote on last edited by
              #29

              @fcarney You mean Anne Boleyn, one of the wifes of king Henry VI which was executed. She was mother of Elisabeth I :-)

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

              jeremy_kJ 1 Reply Last reply
              0
              • jsulmJ jsulm

                @fcarney You mean Anne Boleyn, one of the wifes of king Henry VI which was executed. She was mother of Elisabeth I :-)

                jeremy_kJ Offline
                jeremy_kJ Offline
                jeremy_k
                wrote on last edited by
                #30

                @jsulm said in Boolean in C:

                @fcarney You mean Anne Boleyn, one of the wifes of king Henry VI which was executed. She was mother of Elisabeth I :-)

                Ha! I'm not sure what a Boleyn variable would be. Dangerous in some manner.

                Presumably @fcarney is referring to George Boole.

                Asking a question about code? http://eel.is/iso-c++/testcase/

                Kent-DorfmanK 1 Reply Last reply
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                • J.HilkJ J.Hilk

                  @sierdzio , @JonB

                  are you guys aware, that not is a valid keyword in c++ ?

                  https://en.cppreference.com/w/cpp/keyword/not

                  Kent-DorfmanK Offline
                  Kent-DorfmanK Offline
                  Kent-Dorfman
                  wrote on last edited by
                  #31

                  @J-Hilk said in Boolean in C:

                  are you guys aware, that not is a valid keyword in c++ ?

                  Heretic!
                  and the discussion is about C. ;^P

                  But to the point about superfluous comparisons: I guess is comes down to whether you understand the grammar. If you understand that all comparison operations evaluate to a boolean value (zero, or not zero) then it should become evident that explicit comparisons of booleans to a constant is redundant.

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                  • jeremy_kJ jeremy_k

                    @jsulm said in Boolean in C:

                    @fcarney You mean Anne Boleyn, one of the wifes of king Henry VI which was executed. She was mother of Elisabeth I :-)

                    Ha! I'm not sure what a Boleyn variable would be. Dangerous in some manner.

                    Presumably @fcarney is referring to George Boole.

                    Kent-DorfmanK Offline
                    Kent-DorfmanK Offline
                    Kent-Dorfman
                    wrote on last edited by
                    #32

                    @jeremy_k said in Boolean in C:

                    Ha! I'm not sure what a Boleyn variable would be. Dangerous in some manner.

                    I guess technically I AM, being a decendent of Mary Boleyn...as for being dangerous... :^D

                    JonBJ 1 Reply Last reply
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                    • Kent-DorfmanK Kent-Dorfman

                      @jeremy_k said in Boolean in C:

                      Ha! I'm not sure what a Boleyn variable would be. Dangerous in some manner.

                      I guess technically I AM, being a decendent of Mary Boleyn...as for being dangerous... :^D

                      JonBJ Offline
                      JonBJ Offline
                      JonB
                      wrote on last edited by
                      #33

                      @Kent-Dorfman said in Boolean in C:

                      I guess technically I AM, being a decendent of Mary Boleyn

                      Are you also claiming to be a descendant of Henry VIII? :)

                      Kent-DorfmanK 1 Reply Last reply
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                      • JonBJ JonB

                        @Kent-Dorfman said in Boolean in C:

                        I guess technically I AM, being a decendent of Mary Boleyn

                        Are you also claiming to be a descendant of Henry VIII? :)

                        Kent-DorfmanK Offline
                        Kent-DorfmanK Offline
                        Kent-Dorfman
                        wrote on last edited by
                        #34

                        @JonB said in Boolean in C:

                        Are you also claiming to be a descendant of Henry VIII? :)

                        Claiming is such a strict definition. It is an interesting possibility that historians play with, and I cannot discount how much my cousins look like Henry in his later years (according to paintings)...and we do know that grammy Mary was quite the party girl.

                        1 Reply Last reply
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