diff --git a/include/common/buf.h b/include/common/buf.h
index d39de71..cc670bf 100644
--- a/include/common/buf.h
+++ b/include/common/buf.h
@@ -30,6 +30,7 @@
 
 #include <stdint.h>
 #include <string.h>
+#include <unistd.h>
 
 /* Structure defining a buffer's head */
 struct buffer {