diff --git a/src/lib.rs b/src/lib.rs
index 30eedd62..e12aab06 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -449,7 +449,7 @@ pub struct TcpKeepalive {
         target_os = "openbsd",
         target_os = "redox",
         target_os = "solaris",
-        target_os = "nto",
+        all(target_os = "nto", not(target_env = "nto71_iosock")),
         target_os = "espidf",
         target_os = "vita",
         target_os = "haiku",
@@ -460,7 +460,7 @@ pub struct TcpKeepalive {
         target_os = "openbsd",
         target_os = "redox",
         target_os = "solaris",
-        target_os = "nto",
+        all(target_os = "nto", not(target_env = "nto71_iosock")),
         target_os = "espidf",
         target_os = "vita",
         target_os = "haiku",
@@ -479,7 +479,7 @@ impl TcpKeepalive {
                 target_os = "openbsd",
                 target_os = "redox",
                 target_os = "solaris",
-                target_os = "nto",
+                all(target_os = "nto", not(target_env = "nto71_iosock")),
                 target_os = "espidf",
                 target_os = "vita",
                 target_os = "haiku",
@@ -490,7 +490,7 @@ impl TcpKeepalive {
                 target_os = "openbsd",
                 target_os = "redox",
                 target_os = "solaris",
-                target_os = "nto",
+                all(target_os = "nto", not(target_env = "nto71_iosock")),
                 target_os = "espidf",
                 target_os = "vita",
                 target_os = "haiku",
diff --git a/src/sockaddr.rs b/src/sockaddr.rs
index 120a5466..1e1dc218 100644
--- a/src/sockaddr.rs
+++ b/src/sockaddr.rs
@@ -370,7 +370,7 @@ impl From<SocketAddrV4> for SockAddr {
             target_os = "visionos",
             target_os = "macos",
             target_os = "netbsd",
-            target_os = "nto",
+            all(target_os = "nto", not(target_env = "nto71_iosock")),
             target_os = "openbsd",
             target_os = "tvos",
             target_os = "vxworks",
@@ -414,7 +414,7 @@ impl From<SocketAddrV6> for SockAddr {
             target_os = "visionos",
             target_os = "macos",
             target_os = "netbsd",
-            target_os = "nto",
+            all(target_os = "nto", not(target_env = "nto71_iosock")),
             target_os = "openbsd",
             target_os = "tvos",
             target_os = "vxworks",
@@ -439,7 +439,7 @@ impl fmt::Debug for SockAddr {
             target_os = "visionos",
             target_os = "macos",
             target_os = "netbsd",
-            target_os = "nto",
+            all(target_os = "nto", not(target_env = "nto71_iosock")),
             target_os = "openbsd",
             target_os = "tvos",
             target_os = "vxworks",
diff --git a/src/socket.rs b/src/socket.rs
index da01a77a..4020eba9 100644
--- a/src/socket.rs
+++ b/src/socket.rs
@@ -11,7 +11,10 @@ use std::io::{self, Read, Write};
 #[cfg(not(any(target_os = "redox", target_os = "wasi", target_os = "horizon")))]
 use std::io::{IoSlice, IoSliceMut};
 use std::mem::MaybeUninit;
-#[cfg(not(any(target_os = "nto", target_os = "nuttx")))]
+#[cfg(not(any(
+    all(target_os = "nto", not(target_env = "nto71_iosock")),
+    target_os = "nuttx"
+)))]
 use std::net::Ipv6Addr;
 use std::net::{self, Ipv4Addr, Shutdown};
 #[cfg(any(unix, all(target_os = "wasi", not(target_env = "p1"))))]
@@ -1351,7 +1354,7 @@ impl Socket {
         target_os = "openbsd",
         target_os = "redox",
         target_os = "solaris",
-        target_os = "nto",
+        all(target_os = "nto", not(target_env = "nto71_iosock")),
         target_os = "espidf",
         target_os = "vita",
         target_os = "cygwin",
@@ -1387,7 +1390,7 @@ impl Socket {
         target_os = "openbsd",
         target_os = "redox",
         target_os = "solaris",
-        target_os = "nto",
+        all(target_os = "nto", not(target_env = "nto71_iosock")),
         target_os = "espidf",
         target_os = "vita",
         target_os = "cygwin",
@@ -1425,7 +1428,7 @@ impl Socket {
         target_os = "openbsd",
         target_os = "redox",
         target_os = "fuchsia",
-        target_os = "nto",
+        all(target_os = "nto", not(target_env = "nto71_iosock")),
         target_os = "espidf",
         target_os = "vita",
         target_os = "wasi",
@@ -1465,7 +1468,7 @@ impl Socket {
         target_os = "openbsd",
         target_os = "redox",
         target_os = "fuchsia",
-        target_os = "nto",
+        all(target_os = "nto", not(target_env = "nto71_iosock")),
         target_os = "espidf",
         target_os = "vita",
         target_os = "wasi",
@@ -1686,7 +1689,7 @@ impl Socket {
         target_os = "redox",
         target_os = "solaris",
         target_os = "haiku",
-        target_os = "nto",
+        all(target_os = "nto", not(target_env = "nto71_iosock")),
         target_os = "espidf",
         target_os = "nuttx",
         target_os = "vita",
@@ -1721,7 +1724,7 @@ impl Socket {
         target_os = "redox",
         target_os = "solaris",
         target_os = "haiku",
-        target_os = "nto",
+        all(target_os = "nto", not(target_env = "nto71_iosock")),
         target_os = "espidf",
         target_os = "nuttx",
         target_os = "vita",
@@ -1870,7 +1873,10 @@ impl Socket {
     /// This function specifies a new multicast group for this socket to join.
     /// The address must be a valid multicast address, and `interface` is the
     /// index of the interface to join/leave (or 0 to indicate any interface).
-    #[cfg(not(any(target_os = "nto", target_os = "nuttx")))]
+    #[cfg(not(any(
+        all(target_os = "nto", not(target_env = "nto71_iosock")),
+        target_os = "nuttx"
+    )))]
     pub fn join_multicast_v6(&self, multiaddr: &Ipv6Addr, interface: u32) -> io::Result<()> {
         let mreq = sys::Ipv6Mreq {
             ipv6mr_multiaddr: sys::to_in6_addr(multiaddr),
@@ -1894,7 +1900,10 @@ impl Socket {
     /// For more information about this option, see [`join_multicast_v6`].
     ///
     /// [`join_multicast_v6`]: Socket::join_multicast_v6
-    #[cfg(not(any(target_os = "nto", target_os = "nuttx")))]
+    #[cfg(not(any(
+        all(target_os = "nto", not(target_env = "nto71_iosock")),
+        target_os = "nuttx"
+    )))]
     pub fn leave_multicast_v6(&self, multiaddr: &Ipv6Addr, interface: u32) -> io::Result<()> {
         let mreq = sys::Ipv6Mreq {
             ipv6mr_multiaddr: sys::to_in6_addr(multiaddr),
diff --git a/src/sys/unix.rs b/src/sys/unix.rs
index 65e494bc..ed487394 100644
--- a/src/sys/unix.rs
+++ b/src/sys/unix.rs
@@ -135,7 +135,10 @@ pub(crate) use libc::MSG_TRUNC;
 #[cfg(not(any(target_os = "redox", target_os = "wasi")))]
 pub(crate) use libc::SO_OOBINLINE;
 // Used in `Socket`.
-#[cfg(not(any(target_os = "nto", target_os = "nuttx")))]
+#[cfg(not(any(
+    all(target_os = "nto", not(target_env = "nto71_iosock")),
+    target_os = "nuttx"
+)))]
 pub(crate) use libc::ipv6_mreq as Ipv6Mreq;
 #[cfg(all(feature = "all", target_os = "linux"))]
 pub(crate) use libc::IPV6_HDRINCL;
@@ -198,7 +201,7 @@ pub(crate) use libc::IP_HDRINCL;
     target_os = "solaris",
     target_os = "haiku",
     target_os = "hurd",
-    target_os = "nto",
+    all(target_os = "nto", not(target_env = "nto71_iosock")),
     target_os = "espidf",
     target_os = "nuttx",
     target_os = "vita",
@@ -252,7 +255,7 @@ pub(crate) use libc::{
     target_os = "openbsd",
     target_os = "redox",
     target_os = "fuchsia",
-    target_os = "nto",
+    all(target_os = "nto", not(target_env = "nto71_iosock")),
     target_os = "espidf",
     target_os = "vita",
     target_os = "wasi",
@@ -270,7 +273,8 @@ pub(crate) use libc::{
     target_os = "visionos",
     target_os = "macos",
     target_os = "netbsd",
-    target_os = "nto",
+    all(target_os = "nto", target_env = "nto71_iosock"),
+    target_os = "qnx",
     target_os = "openbsd",
     target_os = "solaris",
     target_os = "tvos",
@@ -289,6 +293,8 @@ pub(crate) use libc::{IPV6_ADD_MEMBERSHIP, IPV6_DROP_MEMBERSHIP};
     target_os = "macos",
     target_os = "netbsd",
     target_os = "openbsd",
+    all(target_os = "nto", target_env = "nto71_iosock"),
+    target_os = "qnx",
     target_os = "solaris",
     target_os = "tvos",
     target_os = "watchos",
@@ -427,6 +433,7 @@ type IovLen = usize;
     target_os = "macos",
     target_os = "netbsd",
     target_os = "nto",
+    target_os = "qnx",
     target_os = "openbsd",
     target_os = "solaris",
     target_os = "tvos",
@@ -1277,7 +1284,7 @@ pub(crate) fn set_tcp_keepalive(fd: RawSocket, keepalive: &TcpKeepalive) -> io::
     #[cfg(not(any(
         target_os = "haiku",
         target_os = "openbsd",
-        target_os = "nto",
+        all(target_os = "nto", not(target_env = "nto71_iosock")),
         target_os = "vita"
     )))]
     if let Some(time) = keepalive.time {
@@ -1297,6 +1304,8 @@ pub(crate) fn set_tcp_keepalive(fd: RawSocket, keepalive: &TcpKeepalive) -> io::
         target_os = "ios",
         target_os = "visionos",
         target_os = "linux",
+        all(target_os = "nto", target_env = "nto71_iosock"),
+        target_os = "qnx",
         target_os = "macos",
         target_os = "netbsd",
         target_os = "tvos",
@@ -1316,7 +1325,7 @@ pub(crate) fn set_tcp_keepalive(fd: RawSocket, keepalive: &TcpKeepalive) -> io::
         }
     }
 
-    #[cfg(target_os = "nto")]
+    #[cfg(all(target_os = "nto", not(target_env = "nto71_iosock")))]
     if let Some(time) = keepalive.time {
         let secs = into_timeval(Some(time));
         unsafe { setsockopt(fd, libc::IPPROTO_TCP, KEEPALIVE_TIME, secs)? }
@@ -1328,7 +1337,7 @@ pub(crate) fn set_tcp_keepalive(fd: RawSocket, keepalive: &TcpKeepalive) -> io::
 #[cfg(not(any(
     target_os = "haiku",
     target_os = "openbsd",
-    target_os = "nto",
+    all(target_os = "nto", not(target_env = "nto71_iosock")),
     target_os = "vita"
 )))]
 fn into_secs(duration: Duration) -> c_int {
@@ -1434,7 +1443,7 @@ pub(crate) fn from_in6_addr(addr: in6_addr) -> Ipv6Addr {
     target_os = "openbsd",
     target_os = "redox",
     target_os = "solaris",
-    target_os = "nto",
+    all(target_os = "nto", not(target_env = "nto71_iosock")),
     target_os = "espidf",
     target_os = "vita",
     target_os = "cygwin",