diff --git a/lib/std/c/dragonfly.zig b/lib/std/c/dragonfly.zig
index 9e4f27bf049e7555ccf67031606aa9a96dd08d12..500b04bcb742de326c668547d1721b1ba1a893c9 100644
--- a/lib/std/c/dragonfly.zig
+++ b/lib/std/c/dragonfly.zig
@@ -838,6 +838,8 @@ pub const EAI = enum(c_int) {
     _,
 };
 
+pub const IFNAMESIZE = 16;
+
 pub const AI = struct {
     pub const PASSIVE = 0x00000001;
     pub const CANONNAME = 0x00000002;
diff --git a/lib/std/c/netbsd.zig b/lib/std/c/netbsd.zig
index 5961b3f490444129f872a389a45741458db21efd..ae0cdf45d3996f755cc2a655fd872439279b19e2 100644
--- a/lib/std/c/netbsd.zig
+++ b/lib/std/c/netbsd.zig
@@ -483,6 +483,8 @@ pub const sockaddr = extern struct {
     };
 };
 
+pub const IFNAMESIZE = 16;
+
 pub const AI = struct {
     /// get address to use bind()
     pub const PASSIVE = 0x00000001;
diff --git a/lib/std/c/openbsd.zig b/lib/std/c/openbsd.zig
index af868ea715c4c89c4881827a2678282e80985278..75a4d6e0e8ee2c444431be2d803b4067350e03c4 100644
--- a/lib/std/c/openbsd.zig
+++ b/lib/std/c/openbsd.zig
@@ -388,6 +388,8 @@ pub const sockaddr = extern struct {
     };
 };
 
+pub const IFNAMESIZE = 16;
+
 pub const AI = struct {
     /// get address to use bind()
     pub const PASSIVE = 1;