diff --git a/src/unix/bsd/apple/mod.rs b/src/unix/bsd/apple/mod.rs
index 9a595e61bfc60..afff006d2ff3c 100644
--- a/src/unix/bsd/apple/mod.rs
+++ b/src/unix/bsd/apple/mod.rs
@@ -819,6 +819,7 @@ pub const MINCORE_MODIFIED: ::c_int = 0x4;
 pub const MINCORE_REFERENCED_OTHER: ::c_int = 0x8;
 pub const MINCORE_MODIFIED_OTHER: ::c_int = 0x10;
 
+pub const AF_UNSPEC: ::c_int = 0;
 pub const AF_UNIX: ::c_int = 1;
 pub const AF_INET: ::c_int = 2;
 pub const AF_INET6: ::c_int = 30;