C++/WinRT is an entirely standard C++ language projection for Windows Runtime (WinRT) APIs, implemented as a header-file-based library, and designed to provide you with first-class access to the modern Windows API. With C++/WinRT, you can author and consume Windows Runtime APIs using any standards-compliant C++17 compiler.
C++/WinRT is part of the [xlang](https://github.com/microsoft/xlang) family of projects that help developers create APIs that can run on multiple platforms and be used with a variety of languages.