1 files changed, 1 insertions, 0 deletions

diff --git a/op.c b/op.c
index 862d297..bb484ce 100644
--- a/op.c
+++ b/op.c
@@ -1,5 +1,6 @@
 #include <stdio.h>
 #include <stdlib.h>
+#include <stddef.h>
 #include <string.h>
 
 #include "readers.h"