diff --git a/lib/std/c/dragonfly.zig b/lib/std/c/dragonfly.zig
index 9e4f27bf04..500b04bcb7 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 5961b3f490..ae0cdf45d3 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 af868ea715..75a4d6e0e8 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;