winrt

Shared C+ ownership and ABI support for Windows Runtime projections. It has no WinUI or Facet dependency. The current implementation targets Windows x64.

[dependencies]
stdlib = "*"
winrt = "*"

import "winrt/runtime" as rt;
// HString::new converts UTF-8 and returns Result[HString, Error].
// Owned HString and Object values release their handles on drop.

Tutorial · Guide · Reference

Run cpc test --filter winrt_ from this package on Windows. Unit tests are in src/runtime.cplus; src/winrt.cplus is the test discovery root. The generated WinUI sample covers native activation, composition, delegates, and shutdown end to end.

Generated delegates expose boxed() for APIs such as WinUI AddHandler that accept an inspectable object. The runtime owns the delegate through a typed IReference<T> box; ordinary typed event subscriptions still use object(). Keep the box for RemoveHandler, and keep the borrowed callback context alive until removal. Boxing does not make a delegate agile.

A generated delegate whose first parameter is an object (an event's sender) records that sender around its callback. After track_events() on a thread, event_sender() there answers the sender of the innermost event being delivered, or null; other threads are not tracked. The pointer is borrowed for the callback's duration. facet_winui uses it to find the window that asked for an alert.