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Boolean in C

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  • J J.Hilk
    26 Oct 2021, 12:15

    @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

    J Offline
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    JonB
    wrote on 26 Oct 2021, 12:17 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?

    J J 2 Replies Last reply 26 Oct 2021, 12:19
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    • J JonB
      26 Oct 2021, 12:17

      @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?

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      jsulm
      Lifetime Qt Champion
      wrote on 26 Oct 2021, 12:19 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

      J 1 Reply Last reply 26 Oct 2021, 12:22
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      • J JonB
        26 Oct 2021, 12:17

        @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 Online
        J Online
        J.Hilk
        Moderators
        wrote on 26 Oct 2021, 12:22 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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        • J jsulm
          26 Oct 2021, 12:19

          @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).

          J Offline
          J Offline
          JonB
          wrote on 26 Oct 2021, 12:22 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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            fcarney
            wrote on 26 Oct 2021, 21:22 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.

            J 1 Reply Last reply 27 Oct 2021, 05:10
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            • F fcarney
              26 Oct 2021, 21:22

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

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              jsulm
              Lifetime Qt Champion
              wrote on 27 Oct 2021, 05:10 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

              J 1 Reply Last reply 27 Oct 2021, 05:27
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              • J jsulm
                27 Oct 2021, 05:10

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

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                jeremy_k
                wrote on 27 Oct 2021, 05:27 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/

                K 1 Reply Last reply 27 Oct 2021, 18:19
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                • J J.Hilk
                  26 Oct 2021, 11:37

                  @sierdzio , @JonB

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

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

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                  Kent-Dorfman
                  wrote on 27 Oct 2021, 18:15 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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                  • J jeremy_k
                    27 Oct 2021, 05:27

                    @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.

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                    K Offline
                    Kent-Dorfman
                    wrote on 27 Oct 2021, 18:19 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

                    J 1 Reply Last reply 27 Oct 2021, 18:33
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                    • K Kent-Dorfman
                      27 Oct 2021, 18:19

                      @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

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                      JonB
                      wrote on 27 Oct 2021, 18:33 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? :)

                      K 1 Reply Last reply 27 Oct 2021, 19:15
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                      • J JonB
                        27 Oct 2021, 18:33

                        @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? :)

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                        K Offline
                        Kent-Dorfman
                        wrote on 27 Oct 2021, 19:15 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.

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