I ran into this same problem today. g++ with -std=c++11 and c++14 does support designated initializers, but you can still get a compilation error “test.cxx:78:9: sorry, unimplemented: non-trivial designated initializers not supported” if you don’t initialize the struct in the order in which it’s members have been defined. As an example struct x { int … Read more
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 … Read more
I’m not sure you can do it in C++. For the stuff that you need to initialize using designated initializers, you can put those separately in a .c file compiled as C99, e.g.: // In common header file typedef union my_union { int i; float f; } my_union; extern const my_union g_var; // In file … Read more
Designated initialisers come in two flavours: 1) It provides a quick way of initialising specific elements in an array: int foo[10] = { [3] = 1, [5] = 2 }; will set all elements to foo to 0, other than index 3 which will be set to 1 and index 5 which will be set … Read more
This is a C99 feature that allows you to set specific fields of the struct by name in an initializer. Before this, the initializer needed to contain just the values, for all fields, in order — which still works, of course. So for the following struct: struct demo_s { int first; int second; int third; … Read more