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  1. Qt
  2. QTBUG-124462

Add a macro for C++20 constexpr

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    • Task
    • Resolution: Unresolved
    • P2: Important
    • None
    • 6.8
    • Core: Other
    • None
    • 3
    • 3ab18f402 (dev)
    • Foundation Sprint 105, Foundation Sprint 106, Foundation Sprint 107, Foundation Sprint 108, Foundation Sprint 109, Foundation Sprint 110, Foundation Sprint 111, Foundation Sprint 112

    Description

      Update: For now, there is only one single use of this macro: explicit destructors can be constexpr. There may be more once we increase our usage of C++20. Therefore, there is no need to add it now. Instead we are adding Q_DECL_CONSTEXPR_DTOR.

      _____________________________________________________________________________________

      Some changes and enhancements were made to the constexpr feature in C++20 making it more flexible.  For example: It allows now dynamic memory allocation and deallocation, constexpr explicit destructors, ect.  https://en.cppreference.com/w/cpp/language/constexpr#:~:text=Constexpr%20lambda-,201907L,-(C%2B%2B20)}}

      Create a macro for C++20 constexpr instead of writing multiple times:

      #if __cpp_constexpr >= 201907L

          constexpr

      #endif 

      I suggest a simple macro CONSTEXPR_20 in qcompilerdetection.h:

      #if __cpp_constexpr >= 201907L

          define CONSTEXPR_20     constexpr
      #else

         define CONSTEXPR_20
      #endif

       

       

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          # Subject Branch Project Status CR V

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              rybouabi Rym Bouabid
              rybouabi Rym Bouabid
              Vladimir Minenko Vladimir Minenko
              Alex Blasche Alex Blasche
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                Created:
                Updated:

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