diff --git a/monitord/plugins/libmplugin_mysql.cpp b/monitord/plugins/libmplugin_mysql.cpp
index 390e2e2..559f987 100644
--- a/monitord/plugins/libmplugin_mysql.cpp
+++ b/monitord/plugins/libmplugin_mysql.cpp
@@ -1,6 +1,7 @@
 
 #include <typeinfo>
 #include <iostream>
+#include <unistd.h>
 
 #ifdef WIN32
 #define usleep Sleep