Designated initializers in C++20

by

According to the C++ 20 Standard (9.3.1 Aggregates. p. #3)

(3.1) — If the initializer list is a designated-initializer-list, the
aggregate shall be of class type, the identifier in each designator
shall name a direct non-static data member of the class, and the
explicitly initialized elements of the aggregate are the elements that
are, or contain, those members.

So you may not use the designated initializer list to initialize data members of base classes.

Use instead the usual list initialization like

Employee e1{ "John", "Wick", 40, 50000 };

or

Employee e1{ { "John", "Wick", 40 }, 50000 };

or as @Jarod42 pointed in a comment you can write

Employee e1{ { .name{"John"}, .surname{"Wick"}, .age{40} }, 50000 };

In this case the direct base class is initialized by a designated initializer list while the class Employe in whole is initialised by a non-designated initializer list.

More Related Contents:

  1. What is a “span” and when should I use one?
  2. Can I take the address of a function defined in standard library?
  3. What exactly are C++ modules?
  4. Why does same_as concept check type equality twice?
  5. How to use source_location in a variadic template function?
  6. Class type non-type template parameter initialization does not compile
  7. C++ Equivalent to Designated Initializers?
  8. non-defaulted operator doesn’t generate == and != in C++20
  9. Why do we require requires requires?
  10. Why does aggregate initialization not work anymore since C++20 if a constructor is explicitly defaulted or deleted?
  11. What is `constinit` in C++20?
  12. Does constraint subsumption only apply to concepts?
  13. C++20 constexpr vector and string not working
  14. C++ Concept that requires a member function with an OutputIterator as parameter
  15. Ramifications of C++20 requiring two’s complement
  16. Familiar template syntax for generic lambdas
  17. ‘auto’ as a template argument placeholder for a function parameter
  18. Comparing 3 modern c++ ways to convert integral values to strings
  19. In which access control context are concepts evaluated?
  20. Is C++20 ‘char8_t’ the same as our old ‘char’?
  21. What is the purpose of C++20 std::common_reference?
  22. Contiguous iterator detection
  23. Why are designated initializers not implemented in g++
  24. Range TS idioms and the mysterious auto &&
  25. Is lambdification of a concept an improvement or bad practice?
  26. Why is operator!= removed in C++20 for many standard library types?
  27. C++ check if statement can be evaluated constexpr
  28. Why must a std::ranges::filter_view object be non-const for querying its elements?
  29. Why don’t I need to specify “typename” before a dependent type in C++20?
  30. How to use C++20’s likely/unlikely attribute in if-else statement

Leave a Comment