refractor based on review

examples/tcp_client.rs

@@ -25,7 +25,10 @@ fn main() -> io::Result<()> {
     };
 
     println!("event: {:?}", event);
-    if event.is_connect_failed() {
+    if event
+        .is_connect_failed()
+        .expect("is connect failed does not support on this platform")
+    {
         println!("connect failed");
     }
 

src/iocp/mod.rs

@@ -684,8 +684,8 @@ impl EventExtra {
 
     /// Check if TCP connect failed.
     #[inline]
-    pub fn is_connect_failed(&self) -> bool {
-        self.flags.intersects(AfdPollMask::CONNECT_FAIL)
+    pub fn is_connect_failed(&self) -> Option<bool> {
+        Some(self.flags.intersects(AfdPollMask::CONNECT_FAIL))
     }
 }
 

src/kqueue.rs

@@ -373,8 +373,8 @@ impl EventExtra {
     }
 
     #[inline]
-    pub fn is_connect_failed(&self) -> bool {
-        unimplemented!("is connect failed is not supported on kqueue");
+    pub fn is_connect_failed(&self) -> Option<bool> {
+        None
     }
 }
 

src/lib.rs

@@ -332,14 +332,58 @@ impl Event {
         self.extra.is_pri()
     }
 
-    /// Tell if this event is the result of a connect failure.
+    /// Tells if this event is the result of a connection failure.
     ///
-    /// This indicates a tcp connection has failed, it corresponds to the `EPOLLERR` along with `EPOLLHUP` event in linux
-    /// and `CONNECT_FAILED` event in windows IOCP.
+    /// This function checks if a TCP connection has failed. It corresponds to the `EPOLLERR`  or `EPOLLHUP` event in Linux
+    /// and `CONNECT_FAILED` event in Windows IOCP.
     ///
-
+    /// # Examples
+    ///
+    /// ```
+    /// use std::{io, net};
+    /// // Assuming polling and socket2 are included as dependencies in Cargo.toml
+    /// use polling::Event;
+    /// use socket2::Type;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let socket = socket2::Socket::new(socket2::Domain::IPV4, Type::STREAM, None)?;
+    ///     let poller = polling::Poller::new()?;
+    ///     unsafe {
+    ///         poller.add(&socket, Event::new(0, true, true))?;
+    ///     }
+    ///     let addr = net::SocketAddr::new(net::Ipv4Addr::LOCALHOST.into(), 8080);
+    ///     socket.set_nonblocking(true)?;
+    ///     let _ = socket.connect(&addr.into());
+    ///
+    ///     let mut events = polling::Events::new();
+    ///
+    ///     events.clear();
+    ///     poller.wait(&mut events, None)?;
+    ///
+    ///     let event = events.iter().next();
+    ///     let Some(event) = event else {
+    ///         println!("no event");
+    ///         return Ok(());
+    ///     };
+    ///
+    ///     println!("event: {:?}", event);
+    ///     if event
+    ///         .is_connect_failed()
+    ///         .expect("is connect failed does not support on this platform")
+    ///     {
+    ///         println!("connect failed");
+    ///     }
+    ///
+    ///     Ok(())
+    /// }
+    /// ```
+    ///
+    /// # Returns
+    ///
+    /// Returns `Some(true)` if the connection has failed, `Some(false)` if the connection has not failed,
+    /// or `None` if the platform does not support detecting this condition.
     #[inline]
-    pub fn is_connect_failed(&self) -> bool {
+    pub fn is_connect_failed(&self) -> Option<bool> {
         self.extra.is_connect_failed()
     }
 

src/poll.rs

@@ -428,10 +428,8 @@ impl EventExtra {
     }
 
     #[inline]
-    pub fn is_connect_failed(&self) -> bool {
-        // need reviewer's special attention, as I do not have access to a system that supports this
-        // this is a guess based on the documentation of `poll()`
-        self.flags.contains(PollFlags::ERR) || self.flags.contains(PollFlags::HUP)
+    pub fn is_connect_failed(&self) -> Option<bool> {
+        Some(self.flags.contains(PollFlags::ERR) || self.flags.contains(PollFlags::HUP))
     }
 }
 

src/port.rs

@@ -253,6 +253,6 @@ impl EventExtra {
 
     #[inline]
     pub fn is_connect_failed(&self) -> bool {
-        self.flags.contains(PollFlags::ERR) || self.flags.contains(PollFlags::HUP)
+        Some(self.flags.contains(PollFlags::ERR) || self.flags.contains(PollFlags::HUP))
     }
 }