This release guarantees thread safety, thus simplifying the public API and providing the user a cleaner approach to building Webview based applications.

Changed

• Webview automatically detects if the thread context is main, and internally re-directs API calls to dispatch_impl appropriately.
• Webview class initialisation MUST happen on the main thread, and Webview will now throw an exception if not.
• run and init SHOULD be called on the main thread, and Webview will now return an error if not.
• The Webview headers are now built with Threads::Threads as a dependency.
• Windows CI tests have pthread statically linked, else MSVC builds will fail to resolve threading library paths.
• Windows CI warmup test uses std::thread to check linkages.

Deprecated

• webview_dispatch is no longer needed due to guaranteed thread safety. The user can make API calls freely from any context.
• webview_destroy. The legacy implementation of this API function was in violation of RAII, and likely to cause undefined behaviour. From a user perspective, it is ambiguous and easily confused with webview_terminate. It now safely re-directs itself to webview_terminate and is no-op if called after webview_terminate or webview_run.

Depends on PR's

• v0.12.1 reference release #1316
• v0.12.2 Refactoring and enabling work #1310

…ew_cc and complete define/implement refactoring.