Clang won't compile anonymous struct

Asked Nov 13 '19 at 09:01

Active Nov 13 '19 at 09:01

Viewed 79 times

I have code below:

struct Foo {
  union {
    struct {
      double d = 1.0;
      double f;
    };
    char c;
  };
};

int main() {
  Foo foo;
}

this code works fine with GCC, but when using Clang, it won't compile:

main.cpp:13:7: error: call to implicitly-deleted default constructor of 'Foo'
  Foo foo;
      ^
main.cpp:3:5: note: default constructor of 'Foo' is implicitly deleted because variant field '' has a non-trivial default constructor
    struct {
    ^

What do I miss?

asked Nov 13 '19 at 09:01

3

It’s a GCC extension. Anonymous are not allowed in the standard. – L. F. Nov 13 '19 at 09:03
1

@L.F. thanks, you should make this as an answer. – Nov 13 '19 at 09:05
1

You might look at `std::variant`which is safer than `union`. – Jarod42 Nov 13 '19 at 09:06
Related: https://stackoverflow.com/questions/2253878/why-does-c-disallow-anonymous-structs – Damon Nov 13 '19 at 09:06
See also [How to add constructors/destructors to an unnamed class?](https://stackoverflow.com/q/21894450/2173773) – Håkon Hægland Nov 13 '19 at 09:11
1

If you remove the value initialization of `double d` it compiles, i.e. change `double d = 1.0` to `double d` – Håkon Hægland Nov 13 '19 at 09:12

Clang won't compile anonymous struct

0 Answers0