diff --git a/ext/sockets/sockets.c b/ext/sockets/sockets.c
index 1df6eaa09d659..6b52bb5c7cc56 100644
--- a/ext/sockets/sockets.c
+++ b/ext/sockets/sockets.c
@@ -545,6 +545,9 @@ static PHP_MINIT_FUNCTION(sockets)
 #ifdef SO_MARK
 	REGISTER_LONG_CONSTANT("SO_MARK",   SO_MARK,    CONST_CS | CONST_PERSISTENT);
 #endif
+#ifdef SO_INCOMING_CPU
+	REGISTER_LONG_CONSTANT("SO_INCOMING_CPU",   SO_INCOMING_CPU,    CONST_CS | CONST_PERSISTENT);
+#endif
 #ifdef TCP_NODELAY
 	REGISTER_LONG_CONSTANT("TCP_NODELAY",   TCP_NODELAY,    CONST_CS | CONST_PERSISTENT);
 #endif