[PATCH] Don't use ManagedStatic.

[Reid Kleckner]

On Mon, Jun 8, 2015 at 9:05 AM, Rui Ueyama <ruiu at google.com> wrote:

> Looks like C++11 guarantees that the following pattern is thread-safe. So
> we can do just like this?
>
> static Foo &getSingleton() {
>   static Foo x;
>   return x;
> }
>

The major limitations with MSVC are:
- Despite the C++11 rules, static local variables are not thread safe in VS
2013, which is the recommended MSVC version.
- Last time we tried call_once, we found that MSVC's implementation of
std::call_once doesn't work until main() starts due, you guessed it, static
initializers.

The thing that does work is using the Win32 API directly.

Another thing that doesn't work is hand-rolling double checked locking
yourself with std::atomic because std::atomic isn't trivially constructible
(oops).
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