diff --git a/uncrustify/src/uncrustify.cpp b/uncrustify/src/uncrustify.cpp

index c65a7ac..3b09d63 100644

--- a/uncrustify/src/uncrustify.cpp

+++ b/uncrustify/src/uncrustify.cpp

@@ -8,6 +8,8 @@

 #define DEFINE_PCF_NAMES

 #define DEFINE_CHAR_TABLE

+#include <unistd.h>

+

 #include "uncrustify_version.h"

 #include "uncrustify_types.h"

 #include "char_table.h"