diff --git a/RSPModelLib/include/RSPModel_errordefs.h b/RSPModelLib/include/RSPModel_errordefs.h
index d707066..6d71ca6 100644
--- a/RSPModelLib/include/RSPModel_errordefs.h
+++ b/RSPModelLib/include/RSPModel_errordefs.h
@@ -7,6 +7,8 @@
  *
  */
 
+#include <stdlib.h>
+
 
 #ifndef RSPMODELLIB_ERRORS_H_
 #define RSPMODELLIB_ERRORS_H_
diff --git a/RSPModelLib/src/RSPModel.c b/RSPModelLib/src/RSPModel.c
index 4ddadaf..b58ed14 100644
--- a/RSPModelLib/src/RSPModel.c
+++ b/RSPModelLib/src/RSPModel.c
@@ -7,6 +7,7 @@
  *
  */
 
+#include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 #include "config.h"