diff --git a/src/unix/bsd/apple/mod.rs b/src/unix/bsd/apple/mod.rs
index 6d0a5bfe32cedcb85cabe26001d1c7416bb76549..ced5170375798ebd3744af5f0ca4d5f051733524 100644
--- a/src/unix/bsd/apple/mod.rs
+++ b/src/unix/bsd/apple/mod.rs
@@ -1862,6 +1862,10 @@ pub const RLIMIT_RSS: ::c_int = RLIMIT_AS;
 pub const RLIMIT_MEMLOCK: ::c_int = 6;
 pub const RLIMIT_NPROC: ::c_int = 7;
 pub const RLIMIT_NOFILE: ::c_int = 8;
+#[deprecated(
+    since = "0.2.64",
+    note = "Not stable across OS versions"
+)]
 pub const RLIM_NLIMITS: ::c_int = 9;
 pub const _RLIMIT_POSIX_FLAG: ::c_int = 0x1000;
 
diff --git a/src/unix/bsd/freebsdlike/dragonfly/mod.rs b/src/unix/bsd/freebsdlike/dragonfly/mod.rs
index fc94fd3c7136e5c65be917d411993c0c095490ba..9e9dc384d7182ebc73c9b6a8d7503f510bf7d345 100644
--- a/src/unix/bsd/freebsdlike/dragonfly/mod.rs
+++ b/src/unix/bsd/freebsdlike/dragonfly/mod.rs
@@ -451,6 +451,10 @@ pub const ENOMEDIUM: ::c_int = 93;
 pub const EASYNC: ::c_int = 99;
 pub const ELAST: ::c_int = 99;
 pub const RLIMIT_POSIXLOCKS: ::c_int = 11;
+#[deprecated(
+    since = "0.2.64",
+    note = "Not stable across OS versions"
+)]
 pub const RLIM_NLIMITS: ::rlim_t = 12;
 
 pub const Q_GETQUOTA: ::c_int = 0x300;
diff --git a/src/unix/bsd/freebsdlike/freebsd/mod.rs b/src/unix/bsd/freebsdlike/freebsd/mod.rs
index 9329d7f84f0204339f8c560918cb874beece11be..c4ad2b3952756a0c8759bddd2ca3bb381de01253 100644
--- a/src/unix/bsd/freebsdlike/freebsd/mod.rs
+++ b/src/unix/bsd/freebsdlike/freebsd/mod.rs
@@ -337,6 +337,10 @@ pub const RLIMIT_NPTS: ::c_int = 11;
 pub const RLIMIT_SWAP: ::c_int = 12;
 pub const RLIMIT_KQUEUES: ::c_int = 13;
 pub const RLIMIT_UMTXP: ::c_int = 14;
+#[deprecated(
+    since = "0.2.64",
+    note = "Not stable across OS versions"
+)]
 pub const RLIM_NLIMITS: ::rlim_t = 15;
 
 pub const Q_GETQUOTA: ::c_int = 0x700;
diff --git a/src/unix/bsd/netbsdlike/netbsd/mod.rs b/src/unix/bsd/netbsdlike/netbsd/mod.rs
index 9401c024bfb65525654e14e9c291a7e70137c811..74b2334d846122a82b68542b5e6b1c11e6120a88 100644
--- a/src/unix/bsd/netbsdlike/netbsd/mod.rs
+++ b/src/unix/bsd/netbsdlike/netbsd/mod.rs
@@ -741,6 +741,10 @@ pub const O_RSYNC : ::c_int = 0x00020000;
 pub const MS_SYNC : ::c_int = 0x4;
 pub const MS_INVALIDATE : ::c_int = 0x2;
 
+#[deprecated(
+    since = "0.2.64",
+    note = "Not stable across OS versions"
+)]
 pub const RLIM_NLIMITS: ::c_int = 12;
 
 pub const EIDRM: ::c_int = 82;
diff --git a/src/unix/bsd/netbsdlike/openbsd/mod.rs b/src/unix/bsd/netbsdlike/openbsd/mod.rs
index b50d815414b74ce61f96b6235ca80f7e9596f383..ffefefd819188bcc2c03862042574d76e9fcf428 100644
--- a/src/unix/bsd/netbsdlike/openbsd/mod.rs
+++ b/src/unix/bsd/netbsdlike/openbsd/mod.rs
@@ -757,6 +757,10 @@ pub const AT_SYMLINK_NOFOLLOW: ::c_int = 0x02;
 pub const AT_SYMLINK_FOLLOW: ::c_int = 0x04;
 pub const AT_REMOVEDIR: ::c_int = 0x08;
 
+#[deprecated(
+    since = "0.2.64",
+    note = "Not stable across OS versions"
+)]
 pub const RLIM_NLIMITS: ::c_int = 9;
 
 pub const SO_TIMESTAMP: ::c_int = 0x0800;
diff --git a/src/unix/linux_like/linux/musl/b32/hexagon.rs b/src/unix/linux_like/linux/musl/b32/hexagon.rs
index c8666925315ff6520f94060f4858b9fc2b924c36..2ff186f0719a4cddfb3d3741bd00f10c850e5f72 100644
--- a/src/unix/linux_like/linux/musl/b32/hexagon.rs
+++ b/src/unix/linux_like/linux/musl/b32/hexagon.rs
@@ -288,6 +288,10 @@ pub const RLIMIT_MEMLOCK: ::c_int = 8;
 pub const RLIMIT_NOFILE: ::c_int = 7;
 pub const RLIMIT_NPROC: ::c_int = 6;
 pub const RLIMIT_RSS: ::c_int = 5;
+#[deprecated(
+    since = "0.2.64",
+    note = "Not stable across OS versions"
+)]
 pub const RLIM_NLIMITS: ::c_int = 16;
 pub const SA_ONSTACK: ::c_int = 0x08000000;
 pub const SA_SIGINFO: ::c_int = 0x00000004;
diff --git a/src/unix/solarish/mod.rs b/src/unix/solarish/mod.rs
index f8a64547d4cb06e203986e06930a91ce248e24ac..5582e271d6815c654f652df4122fb7821c835fdd 100644
--- a/src/unix/solarish/mod.rs
+++ b/src/unix/solarish/mod.rs
@@ -1199,6 +1199,10 @@ pub const RLIMIT_NOFILE: ::c_int = 5;
 pub const RLIMIT_VMEM: ::c_int = 6;
 pub const RLIMIT_AS: ::c_int = RLIMIT_VMEM;
 
+#[deprecated(
+    since = "0.2.64",
+    note = "Not stable across OS versions"
+)]
 pub const RLIM_NLIMITS: rlim_t = 7;
 pub const RLIM_INFINITY: rlim_t = 0x7fffffff;