diff --git a/src/unix/bsd/mod.rs b/src/unix/bsd/mod.rs
index b04b15fe..118daf49 100644
--- a/src/unix/bsd/mod.rs
+++ b/src/unix/bsd/mod.rs
@@ -390,9 +390,15 @@ extern {
     pub fn getloadavg(loadavg: *mut ::c_double, nelem: ::c_int) -> ::c_int;
     pub fn if_nameindex() -> *mut if_nameindex;
     pub fn if_freenameindex(ptr: *mut if_nameindex);
+
+    #[cfg(any(target_os = "macos", target_os = "freebsd", target_os = "dragonfly"))]
+    pub fn getdomainname(name: *mut ::c_char, len: ::c_int) -> ::c_int;
+    #[cfg(any(target_os = "macos", target_os = "freebsd", target_os = "dragonfly"))]
+    pub fn setdomainname(name: *const ::c_char, len: ::c_int) -> ::c_int;
+    #[cfg(not(any(target_os = "macos", target_os = "freebsd", target_os = "dragonfly")))]
     pub fn getdomainname(name: *mut ::c_char, len: ::size_t) -> ::c_int;
+    #[cfg(not(any(target_os = "macos", target_os = "freebsd", target_os = "dragonfly")))]
     pub fn setdomainname(name: *const ::c_char, len: ::size_t) -> ::c_int;
-    pub fn gethostname(name: *mut ::c_char, len: ::size_t) -> ::c_int;
     pub fn getpeereid(socket: ::c_int,
                       euid: *mut ::uid_t,
                       egid: *mut ::gid_t) -> ::c_int;