Fix reset to Poll after the event loop starts

README.md

@@ -41,6 +41,7 @@ use winit::{
 
 fn main() {
     let event_loop = EventLoop::new();
+    event_loop.set_control_flow(ControlFlow::Wait);
     let window = WindowBuilder::new().build(&event_loop).unwrap();
 
     event_loop.run(move |event, elwt| {

src/lib.rs

@@ -49,15 +49,16 @@
 //! let event_loop = EventLoop::new().unwrap();
 //! let window = WindowBuilder::new().build(&event_loop).unwrap();
 //!
-//! event_loop.run(move |event, elwt| {
-//!     // ControlFlow::Poll continuously runs the event loop, even if the OS hasn't
-//!     // dispatched any events. This is ideal for games and similar applications.
-//!     elwt.set_control_flow(ControlFlow::Poll);
+//! // ControlFlow::Poll continuously runs the event loop, even if the OS hasn't
+//! // dispatched any events. This is ideal for games and similar applications.
+//! event_loop.set_control_flow(ControlFlow::Poll);
 //!
-//!     // ControlFlow::Wait pauses the event loop if no events are available to process.
-//!     // This is ideal for non-game applications that only update in response to user
-//!     // input, and uses significantly less power/CPU time than ControlFlow::Poll.
-//!     elwt.set_control_flow(ControlFlow::Wait);
+//! // ControlFlow::Wait pauses the event loop if no events are available to process.
+//! // This is ideal for non-game applications that only update in response to user
+//! // input, and uses significantly less power/CPU time than ControlFlow::Poll.
+//! event_loop.set_control_flow(ControlFlow::Wait);
+//!
+//! event_loop.run(move |event, elwt| {
 //!     match event {
 //!         Event::WindowEvent {
 //!             event: WindowEvent::CloseRequested,

src/platform_impl/android/mod.rs

@@ -526,7 +526,6 @@ impl<T: 'static> EventLoop<T> {
             // than once
             self.pending_redraw = false;
             self.cause = StartCause::Init;
-            self.set_control_flow(ControlFlow::default());
 
             // run the initial loop iteration
             self.single_iteration(None, &mut callback);
@@ -637,10 +636,6 @@ impl<T: 'static> EventLoop<T> {
         }
     }
 
-    fn set_control_flow(&self, control_flow: ControlFlow) {
-        self.window_target.p.set_control_flow(control_flow)
-    }
-
     fn control_flow(&self) -> ControlFlow {
         self.window_target.p.control_flow()
     }

src/platform_impl/ios/app_state.rs

@@ -234,7 +234,7 @@ impl AppState {
         };
         self.set_state(AppStateImpl::ProcessingEvents {
             event_handler,
-            active_control_flow: ControlFlow::Poll,
+            active_control_flow: self.control_flow,
             queued_gpu_redraws,
         });
         (windows, events)
@@ -523,11 +523,6 @@ pub fn did_finish_launching(mtm: MainThreadMarker) {
         s => bug!("unexpected state {:?}", s),
     };
 
-    // start waking up the event loop now!
-    bug_assert!(
-        this.control_flow == ControlFlow::Poll,
-        "unexpectedly not setup to `Poll` on launch!"
-    );
     this.waker.start();
 
     // have to drop RefMut because the window setup code below can trigger new events

src/platform_impl/linux/wayland/event_loop/mod.rs

@@ -227,11 +227,6 @@ impl<T: 'static> EventLoop<T> {
         if !self.loop_running {
             self.loop_running = true;
 
-            // Reset the internal state for the loop as we start running to
-            // ensure consistent behaviour in case the loop runs and exits more
-            // than once.
-            self.set_control_flow(ControlFlow::Poll);
-
             // Run the initial loop iteration.
             self.single_iteration(&mut callback, StartCause::Init);
         }
@@ -611,10 +606,6 @@ impl<T: 'static> EventLoop<T> {
         })
     }
 
-    fn set_control_flow(&self, control_flow: ControlFlow) {
-        self.window_target.p.set_control_flow(control_flow)
-    }
-
     fn control_flow(&self) -> ControlFlow {
         self.window_target.p.control_flow()
     }

src/platform_impl/linux/x11/mod.rs

@@ -439,11 +439,6 @@ impl<T: 'static> EventLoop<T> {
         if !self.loop_running {
             self.loop_running = true;
 
-            // Reset the internal state for the loop as we start running to
-            // ensure consistent behaviour in case the loop runs and exits more
-            // than once.
-            self.set_control_flow(ControlFlow::Poll);
-
             // run the initial loop iteration
             self.single_iteration(&mut callback, StartCause::Init);
         }
@@ -646,10 +641,6 @@ impl<T: 'static> EventLoop<T> {
         }
     }
 
-    fn set_control_flow(&self, control_flow: ControlFlow) {
-        self.target.p.set_control_flow(control_flow)
-    }
-
     fn control_flow(&self) -> ControlFlow {
         self.target.p.control_flow()
     }

src/platform_impl/macos/app_state.rs

@@ -199,7 +199,6 @@ impl Handler {
         // looks like there have been recuring re-entrancy issues with callback handling that might
         // make that awkward)
         self.running.store(false, Ordering::Relaxed);
-        *self.control_flow.lock().unwrap() = ControlFlow::default();
         self.set_stop_app_on_redraw_requested(false);
         self.set_stop_app_before_wait(false);
         self.set_stop_app_after_wait(false);

src/platform_impl/windows/event_loop/runner.rs

@@ -115,7 +115,7 @@ impl<T> EventLoopRunner<T> {
             interrupt_msg_dispatch,
             runner_state,
             panic_error,
-            control_flow,
+            control_flow: _,
             exit,
             last_events_cleared: _,
             event_handler,
@@ -124,7 +124,6 @@ impl<T> EventLoopRunner<T> {
         interrupt_msg_dispatch.set(false);
         runner_state.set(RunnerState::Uninitialized);
         panic_error.set(None);
-        control_flow.set(ControlFlow::default());
         exit.set(None);
         event_handler.set(None);
     }

src/window.rs

@@ -45,6 +45,7 @@ pub use raw_window_handle;
 /// };
 ///
 /// let mut event_loop = EventLoop::new().unwrap();
+/// event_loop.set_control_flow(ControlFlow::Wait);
 /// let window = Window::new(&event_loop).unwrap();
 ///
 /// event_loop.run(move |event, elwt| {