socket2 0.3.19

Utilities for handling networking sockets with a maximal amount of configuration possible intended.
Documentation
diff --git a/src/socket.rs b/src/socket.rs
index 725ad2a..3f7b499 100644
--- a/src/socket.rs
+++ b/src/socket.rs
@@ -963,6 +963,26 @@ fn inner(&self) -> &sys::Socket {
     }
 }
 
+/// Socket options get/set using `SOL_SOCKET`.
+///
+/// Additional documentation can be found in documentation of the OS.
+/// * Linux: <https://man7.org/linux/man-pages/man7/socket.7.html>
+/// * Windows: <https://docs.microsoft.com/en-us/windows/win32/winsock/sol-socket-socket-options>
+impl Socket {
+    /// Gets the value of the `SO_ACCEPTCONN` option on this socket.
+    ///
+    /// Returns `true` if this socket has been marked to accept connections with
+    /// [`listen`].
+    ///
+    /// [`listen`]: Socket::listen
+    pub fn is_listener(&self) -> io::Result<bool> {
+        unsafe {
+            getsockopt::<c_int>(self.inner, sys::SOL_SOCKET, sys::SO_ACCEPTCONN)
+                .map(|is_listener| is_listener != 0)
+        }
+    }
+}
+
 /// Socket options for TCP socket, get/set using `IPPROTO_TCP`.
 ///
 /// Additional documentation can be found in documentation of the OS.
diff --git a/src/sys/unix.rs b/src/sys/unix.rs
index 60593a1..51b916a 100644
--- a/src/sys/unix.rs
+++ b/src/sys/unix.rs
@@ -54,8 +54,8 @@
 pub(crate) use libc::MSG_OOB;
 pub(crate) use libc::{
     IPPROTO_IP, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, IPV6_MULTICAST_LOOP, IPV6_UNICAST_HOPS,
-    IPV6_V6ONLY, IP_MULTICAST_LOOP, IP_MULTICAST_TTL, IP_TTL, MSG_PEEK, SOL_SOCKET, SO_BROADCAST,
-    SO_ERROR, TCP_NODELAY,
+    IPV6_V6ONLY, IP_MULTICAST_LOOP, IP_MULTICAST_TTL, IP_TTL, MSG_PEEK, SOL_SOCKET, SO_ACCEPTCONN,
+    SO_BROADCAST, SO_ERROR, TCP_NODELAY,
 };
 
 // See this type in the Windows file.
diff --git a/src/sys/windows.rs b/src/sys/windows.rs
index 663b63f..a212525 100644
--- a/src/sys/windows.rs
+++ b/src/sys/windows.rs
@@ -60,7 +60,7 @@
 pub(crate) use winapi::um::ws2tcpip::socklen_t;
 // Used in `Socket`.
 pub(crate) use winapi::shared::ws2def::{
-    IPPROTO_IP, SOL_SOCKET, SO_BROADCAST, SO_ERROR, TCP_NODELAY,
+    IPPROTO_IP, SOL_SOCKET, SO_ACCEPTCONN, SO_BROADCAST, SO_ERROR, TCP_NODELAY,
 };
 pub(crate) use winapi::shared::ws2ipdef::{
     IPV6_MULTICAST_HOPS, IPV6_MULTICAST_LOOP, IPV6_UNICAST_HOPS, IPV6_V6ONLY, IP_MULTICAST_LOOP,
diff --git a/tests/options.rs b/tests/options.rs
index 9c3d1c2..2d256a7 100644
--- a/tests/options.rs
+++ b/tests/options.rs
@@ -1,6 +1,8 @@
 //! Tests for getting and setting socket options.
 
-use socket2::{Domain, Socket, Type};
+use std::net::SocketAddr;
+
+use socket2::{Domain, Protocol, Socket, Type};
 
 /// Macro to create a simple test to set and get a socket option.
 macro_rules! test {
@@ -86,6 +88,22 @@ fn $get_fn() {
     set_mark(123)
 );
 
+#[test]
+fn is_listener() {
+    // TODO: IPv6.
+
+    let socket = Socket::new(Domain::IPV4, Type::STREAM, Some(Protocol::TCP))
+        .expect("failed to create `Socket`");
+    //assert_eq!(socket.is_listener().unwrap(), false);
+
+    let addr: SocketAddr = "127.0.0.1:0".parse().unwrap();
+    let addr = addr.into();
+    socket.bind(&addr).unwrap();
+    socket.listen(1).unwrap();
+    dbg!(socket.is_listener());
+    assert_eq!(socket.is_listener().unwrap(), true);
+}
+
 test!(IPv4 ttl, set_ttl(40));
 #[cfg(not(windows))] // TODO: returns `WSAENOPROTOOPT` (10042) on Windows.
 test!(IPv4 broadcast, set_broadcast(true));