diff --git a/lib/std/os/bits/freebsd.zig b/lib/std/os/bits/freebsd.zig
index 6378dcaf8d..71233adb36 100644
--- a/lib/std/os/bits/freebsd.zig
+++ b/lib/std/os/bits/freebsd.zig
@@ -553,6 +553,9 @@ pub const EV_ONESHOT = 0x0010;
 /// clear event state after reporting
 pub const EV_CLEAR = 0x0020;
 
+/// error, event data contains errno
+pub const EV_ERROR = 0x4000;
+
 /// force immediate event output
 /// ... with or without EV_ERROR
 /// ... use KEVENT_FLAG_ERROR_EVENTS