diff --git a/mcop/iomanager.cpp b/mcop/iomanager.cpp
index 897a61c..31709f9 100644
--- a/mcop/iomanager.cpp
+++ b/mcop/iomanager.cpp
@@ -29,6 +29,9 @@
 #include "thread.h"
 #include <stdio.h>
 #include <fcntl.h>
+#if defined(__dilos__)
+#include <string.h>  /* in illumos memset() is defined here */
+#endif /* __dilos__ */
 
 #ifdef HAVE_SYS_SELECT_H
 #include <sys/select.h>		// Needed on some systems.