Add cygwin support

.github/workflows/main.yml

@@ -83,6 +83,7 @@ jobs:
           - sparcv9-sun-solaris
           - x86_64-apple-darwin
           - x86_64-apple-ios
+          - x86_64-pc-cygwin
           - x86_64-pc-solaris
           # Fails with:
           # `rror calling dlltool 'x86_64-w64-mingw32-dlltool': No such file or

src/lib.rs

@@ -516,6 +516,7 @@ impl TcpKeepalive {
         target_os = "tvos",
         target_os = "watchos",
         target_os = "windows",
+        target_os = "cygwin",
     ))]
     pub const fn with_interval(self, interval: Duration) -> Self {
         Self {
@@ -543,6 +544,7 @@ impl TcpKeepalive {
             target_os = "netbsd",
             target_os = "tvos",
             target_os = "watchos",
+            target_os = "cygwin",
         )
     ))]
     pub const fn with_retries(self, retries: u32) -> Self {

src/socket.rs

@@ -271,6 +271,7 @@ impl Socket {
             target_os = "linux",
             target_os = "netbsd",
             target_os = "openbsd",
+            target_os = "cygwin",
         ))]
         return self._accept4(libc::SOCK_CLOEXEC);
 
@@ -284,6 +285,7 @@ impl Socket {
             target_os = "linux",
             target_os = "netbsd",
             target_os = "openbsd",
+            target_os = "cygwin",
         )))]
         {
             let (socket, addr) = self.accept_raw()?;
@@ -752,6 +754,7 @@ const fn set_common_type(ty: Type) -> Type {
         target_os = "linux",
         target_os = "netbsd",
         target_os = "openbsd",
+        target_os = "cygwin",
     ))]
     let ty = ty._cloexec();
 
@@ -781,6 +784,7 @@ fn set_common_flags(socket: Socket) -> io::Result<Socket> {
             target_os = "openbsd",
             target_os = "espidf",
             target_os = "vita",
+            target_os = "cygwin",
         ))
     ))]
     socket._set_cloexec(true)?;
@@ -956,7 +960,7 @@ impl Socket {
     /// For more information about this option, see [`set_passcred`].
     ///
     /// [`set_passcred`]: Socket::set_passcred
-    #[cfg(all(unix, target_os = "linux"))]
+    #[cfg(all(unix, any(target_os = "linux", target_os = "cygwin")))]
     pub fn passcred(&self) -> io::Result<bool> {
         unsafe {
             getsockopt::<c_int>(self.as_raw(), sys::SOL_SOCKET, sys::SO_PASSCRED)
@@ -968,7 +972,7 @@ impl Socket {
     ///
     /// If this option is enabled, enables the receiving of the `SCM_CREDENTIALS`
     /// control messages.
-    #[cfg(all(unix, target_os = "linux"))]
+    #[cfg(all(unix, any(target_os = "linux", target_os = "cygwin")))]
     pub fn set_passcred(&self, passcred: bool) -> io::Result<()> {
         unsafe {
             setsockopt(
@@ -1254,6 +1258,7 @@ impl Socket {
         target_os = "nto",
         target_os = "espidf",
         target_os = "vita",
+        target_os = "cygwin",
     )))]
     pub fn join_multicast_v4_n(
         &self,
@@ -1287,6 +1292,7 @@ impl Socket {
         target_os = "nto",
         target_os = "espidf",
         target_os = "vita",
+        target_os = "cygwin",
     )))]
     pub fn leave_multicast_v4_n(
         &self,
@@ -1577,6 +1583,7 @@ impl Socket {
         target_os = "nto",
         target_os = "espidf",
         target_os = "vita",
+        target_os = "cygwin",
     )))]
     pub fn set_recv_tos_v4(&self, recv_tos: bool) -> io::Result<()> {
         unsafe {
@@ -1608,6 +1615,7 @@ impl Socket {
         target_os = "nto",
         target_os = "espidf",
         target_os = "vita",
+        target_os = "cygwin",
     )))]
     pub fn recv_tos_v4(&self) -> io::Result<bool> {
         unsafe {
@@ -1978,6 +1986,7 @@ impl Socket {
             target_os = "hurd",
             target_os = "espidf",
             target_os = "vita",
+            target_os = "cygwin",
         ))
     ))]
     pub fn recv_hoplimit_v6(&self) -> io::Result<bool> {
@@ -2006,6 +2015,7 @@ impl Socket {
             target_os = "hurd",
             target_os = "espidf",
             target_os = "vita",
+            target_os = "cygwin",
         ))
     ))]
     pub fn set_recv_hoplimit_v6(&self, recv_hoplimit: bool) -> io::Result<()> {
@@ -2063,6 +2073,7 @@ impl Socket {
             target_os = "netbsd",
             target_os = "tvos",
             target_os = "watchos",
+            target_os = "cygwin",
         )
     ))]
     pub fn keepalive_interval(&self) -> io::Result<Duration> {
@@ -2092,6 +2103,7 @@ impl Socket {
             target_os = "netbsd",
             target_os = "tvos",
             target_os = "watchos",
+            target_os = "cygwin",
         )
     ))]
     pub fn keepalive_retries(&self) -> io::Result<u32> {