diff --git a/io/io_createfile.c b/io/io_createfile.c
index 4344849..a58dfb4 100644
--- a/io/io_createfile.c
+++ b/io/io_createfile.c
@@ -1,3 +1,4 @@
+#define _FILE_OFFSET_BITS 64
 #include <unistd.h>
 #include <fcntl.h>
 #include "io_internal.h"
diff --git a/io/io_readfile.c b/io/io_readfile.c
index 99261f5..177502b 100644
--- a/io/io_readfile.c
+++ b/io/io_readfile.c
@@ -1,3 +1,4 @@
+#define _FILE_OFFSET_BITS 64
 #include <unistd.h>
 #include <fcntl.h>
 #include "io_internal.h"