What is _In_ in C++?

Question

I have searched this up rather a lot, but come up with no helpful results.

I am currently trying to program simple DirextX game for Windows 8 Metro, and have come ac

Answer 1

It is a SAL annotation, used for code analysis. The annotations themselves are defined as macros that, in normal builds, expand to nothing.

The ^ and ref class are features of C++/CX, a set of language extensions developed to make it easier to build Metro style apps for Windows 8 in C++. Neither is a part of standard C++. The documentation (linked previously) has links to tutorials and references describing the language extensions.