diff --git a/src_main/core/piincludes.h b/src_main/core/piincludes.h
index 65faa6dd..882f5fb8 100755
--- a/src_main/core/piincludes.h
+++ b/src_main/core/piincludes.h
@@ -23,6 +23,7 @@
 #include "pibase.h"
 #include "piflags.h"
 #include "pimonitor.h"
+#include <sys/types.h>
 #ifdef PIP_STD_IOSTREAM
 #  include <iostream>
 #endif