diff --git a/examples/tcp_client.rs b/examples/tcp_client.rs
index 0a71cf3..aa9d708 100644
--- a/examples/tcp_client.rs
+++ b/examples/tcp_client.rs
@@ -2,7 +2,6 @@ use std::{io, net};
 
 use polling::Event;
 use socket2::Type;
-use tracing::event;
 
 fn main() -> io::Result<()> {
     let socket = socket2::Socket::new(socket2::Domain::IPV4, Type::STREAM, None)?;
@@ -12,13 +11,13 @@ fn main() -> io::Result<()> {
     }
     let addr = net::SocketAddr::new(net::Ipv4Addr::LOCALHOST.into(), 8080);
     socket.set_nonblocking(true)?;
-    let mut res = socket.connect(&addr.into());
+    let res = socket.connect(&addr.into());
 
     let mut events = polling::Events::new();
-    while let Err(ref e) = res {
-        if e.kind() != io::ErrorKind::WouldBlock {
-            return Err(io::Error::new(e.kind(), e.to_string()));
-        }
+    // while let Err(ref e) = res {
+        // if e.kind() != io::ErrorKind::WouldBlock {
+        //     return Err(io::Error::new(e.kind(), e.to_string()));
+        // }
 
         events.clear();
         poller.wait(&mut events, None)?;
@@ -26,16 +25,16 @@ fn main() -> io::Result<()> {
         let event = events.iter().next();
         if event.is_none() {
             println!("no event");
-            break;
+            // break;
         }
 
         let event = event.unwrap();
         println!("event: {:?}", event);
         if event.is_connect_failed() {
             println!("connect failed");
-            break;
+            // break;
         }
-    }
+    // }
 
     Ok(())
 }
diff --git a/src/epoll.rs b/src/epoll.rs
index 606dd1c..66067be 100644
--- a/src/epoll.rs
+++ b/src/epoll.rs
@@ -365,6 +365,11 @@ impl EventExtra {
     pub fn is_pri(&self) -> bool {
         self.flags.contains(epoll::EventFlags::PRI)
     }
+
+    #[inline]
+    pub fn is_connect_failed(&self) -> bool {
+        self.flags.contains(epoll::EventFlags::ERR) && self.flags.contains(epoll::EventFlags::HUP)
+    }
 }
 
 /// The notifier for Linux.
diff --git a/src/lib.rs b/src/lib.rs
index 1870e63..e0e78f6 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -334,7 +334,10 @@ impl Event {
 
     /// Tell if this event is the result of a connect failure.
     /// 
-    /// This indicates that a non-blocking connect operation has failed. 
+    /// 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.
+    /// 
+
     #[inline]
     pub fn is_connect_failed(&self) -> bool {
         self.extra.is_connect_failed()