diff --git a/lib/socket.h b/lib/socket.h
index a267b1dc9..26952d625 100644
--- a/lib/socket.h
+++ b/lib/socket.h
@@ -6,6 +6,7 @@
 #include <sys/types.h>
 #include <unistd.h>
 #include <fcntl.h>
+#include <errno.h>