Return window::Id in window::open

examples/multi_window/src/main.rs

@@ -40,12 +40,13 @@ enum Message {
 
 impl Example {
     fn new() -> (Self, Task<Message>) {
+        let (_id, open) = window::open(window::Settings::default());
+
         (
             Self {
                 windows: BTreeMap::new(),
             },
-            window::open(window::Settings::default())
+            open.map(Message::WindowOpened),
-                .map(Message::WindowOpened),
         )
     }
 
@@ -74,10 +75,12 @@ impl Example {
                             },
                         );
 
-                        window::open(window::Settings {
+                        let (_id, open) = window::open(window::Settings {
                             position,
                             ..window::Settings::default()
-                        })
+                        });
+
+                        open
                     })
                     .map(Message::WindowOpened)
             }

runtime/src/window.rs

@@ -218,12 +218,15 @@ pub fn close_requests() -> Subscription<Id> {
 
 /// Opens a new window with the given [`Settings`]; producing the [`Id`]
 /// of the new window on completion.
-pub fn open(settings: Settings) -> Task<Id> {
+pub fn open(settings: Settings) -> (Id, Task<Id>) {
     let id = Id::unique();
 
+    (
+        id,
         task::oneshot(|channel| {
             crate::Action::Window(Action::Open(id, settings, channel))
-    })
+        }),
+    )
 }
 
 /// Closes the window with `id`.

winit/src/program.rs

@@ -207,8 +207,9 @@ where
     let task = if let Some(window_settings) = window_settings {
         let mut task = Some(task);
 
-        runtime::window::open(window_settings)
+        let (_id, open) = runtime::window::open(window_settings);
-            .then(move |_| task.take().unwrap_or(Task::none()))
+
+        open.then(move |_| task.take().unwrap_or(Task::none()))
     } else {
         task
     };