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#![cfg(any(
target_os = "windows",
target_os = "macos",
target_os = "android",
target_os = "linux",
target_os = "dragonfly",
target_os = "freebsd",
target_os = "netbsd",
target_os = "openbsd"
))]
use crate::{
event::Event,
event_loop::{ControlFlow, EventLoop, EventLoopWindowTarget},
};
/// Additional methods on `EventLoop` to return control flow to the caller.
pub trait EventLoopExtRunReturn {
/// A type provided by the user that can be passed through `Event::UserEvent`.
type UserEvent;
/// Initializes the `winit` event loop.
///
/// Unlike `run`, this function accepts non-`'static` (i.e. non-`move`) closures and returns
/// control flow to the caller when `control_flow` is set to `ControlFlow::Exit`.
///
/// # Caveats
/// Despite its appearance at first glance, this is *not* a perfect replacement for
/// `poll_events`. For example, this function will not return on Windows or macOS while a
/// window is getting resized, resulting in all application logic outside of the
/// `event_handler` closure not running until the resize operation ends. Other OS operations
/// may also result in such freezes. This behavior is caused by fundamental limitations in the
/// underlying OS APIs, which cannot be hidden by `winit` without severe stability repercussions.
///
/// You are strongly encouraged to use `run`, unless the use of this is absolutely necessary.
fn run_return<F>(&mut self, event_handler: F)
where
F: FnMut(
Event<'_, Self::UserEvent>,
&EventLoopWindowTarget<Self::UserEvent>,
&mut ControlFlow,
);
}
impl<T> EventLoopExtRunReturn for EventLoop<T> {
type UserEvent = T;
fn run_return<F>(&mut self, event_handler: F)
where
F: FnMut(
Event<'_, Self::UserEvent>,
&EventLoopWindowTarget<Self::UserEvent>,
&mut ControlFlow,
),
{
self.event_loop.run_return(event_handler)
}
}