Threads, shread and TLS

[Adam Conner-Sax]

So, I thought I sort of understood "shared" and now I think I don't.

If I have a class:

class foo {
  int x;
  static int y;
  shared static int z;

}

So x is one instance per class and is thread-local?
y is one instance per thread?
z is one instance per application, i.e., global?

If that's true (and I realize it might not be), and I want to initialize these
variables in constructors, how does that work?

I think

class foo {
...(as before)

this() { x = 2; } // ok

static this() { y = 3; } // is this called once per thread?

shared static this() { z = 3;} // also, okay, called before main
}

but I don't understand what happens with threads and the "static this"
constructor.  How/when are the thread-local copies constructed?  How do you
initialize/construct the thread-local static data?

Thanks!

Adam