diff --git a/dm/DM.cpp b/dm/DM.cpp
index 139e9eb..64f0e07 100644
--- a/dm/DM.cpp
+++ b/dm/DM.cpp
@@ -5,6 +5,8 @@
  * found in the LICENSE file.
  */
 
+#include <unistd.h>
+
 #include "CrashHandler.h"
 #include "DMJsonWriter.h"
 #include "DMSrcSink.h"