Does the C "magic static" pattern work for all initialization styles?-CodePudding

I understand that the C "magic static" pattern guarantees thread-safe initialization of a local variable, since C 11. Does this hold true no matter how the local is initialized?

int some_expensive_func();

void test()
{
  static int attempt1{some_expensive_func()};
  static int attempt2 = {some_expensive_func()};
  static int attempt3 = some_expensive_func();
  static int attempt4(some_expensive_func());
}

I have an in-house static-analysis checker that's complaining about the thread-safety of the third style shown above, but I think it's OK, and I'm looking for confirmation. Thanks.

CodePudding user response：

Yes, all initialization styles are thread-safe for local static variables (since C 11). The only thing that wouldn't be thread-safe is something that's not actually an initialization, e.g., something like this:

static int x;               // zero-initialized on program startup
x = some_expensive_func();  // this is assignment, not initialization