diff --git a/src/branch2.cpp b/src/branch2.cpp
index 28616210..338c9f06 100644
--- a/src/branch2.cpp
+++ b/src/branch2.cpp
@@ -5,6 +5,7 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
+#include <unistd.h>
 
 
 Branch2::Branch2()