为单例创建静态实例的这些方法有何不同？

I have had a bug recently that only manifested itself when the library was built as a release build rather than a debug build. The library is a .NET dll with a COM wrapper and I am using CoCreateInstance to create a class from the dll in an unmanaged c++ app. When I finally tracked the bug down it was caused by accessing a singleton object. I had the singleton instance declared like so:I have had a bug recently that only manifested