diff --git a/memfile.cpp b/memfile.cpp
index be81c4f4..a363b0b9 100644
--- a/memfile.cpp
+++ b/memfile.cpp
@@ -2,6 +2,7 @@
 #include <string.h>
 #include <unistd.h>
 #include <sys/mman.h>
+#include <errno.h>
 #include "memfile.hpp"
 
 #define INCREMENT 131072