diff --git a/quad_double/qd/src/dd_real.cpp b/quad_double/qd/src/dd_real.cpp
index 4c6dcbc02..f6535f0f7 100644
--- a/quad_double/qd/src/dd_real.cpp
+++ b/quad_double/qd/src/dd_real.cpp
@@ -17,6 +17,7 @@
 #include <iostream>
 #include <iomanip>
 #include <string>
+#include <algorithm>
 
 #include "config.h"
 #include <qd/dd_real.h>
diff --git a/quad_double/qd/src/qd_real.cpp b/quad_double/qd/src/qd_real.cpp
index 70988ffed..21b9577cf 100644
--- a/quad_double/qd/src/qd_real.cpp
+++ b/quad_double/qd/src/qd_real.cpp
@@ -17,6 +17,7 @@
 #include <iostream>
 #include <iomanip>
 #include <string>
+#include <algorithm>
 
 #include "config.h"
 #include <qd/qd_real.h>