diff --git a/sway/config/output.c b/sway/config/output.c
index 513d03e0f..e0395f825 100644
--- a/sway/config/output.c
+++ b/sway/config/output.c
@@ -1,4 +1,8 @@
 #define _POSIX_C_SOURCE 200809L
+#ifdef __FreeBSD__
+// for SOCK_CLOEXEC
+#define __BSD_VISIBLE 1
+#endif
 #include <assert.h>
 #include <fcntl.h>
 #include <stdbool.h>