diff --git a/services/src/peruser_session.cpp b/services/src/peruser_session.cpp
index 51aec8a..8430fbc 100644
--- a/services/src/peruser_session.cpp
+++ b/services/src/peruser_session.cpp
@@ -13,6 +13,7 @@
  * limitations under the License.
  */
 
+#include "unistd.h"
 #include "platform.h"
 #include "parcel.h"
 #include "message_parcel.h"