diff --git a/src/qjackctlGraph.cpp b/src/qjackctlGraph.cpp
index bd0ca71..fe45f1f 100644
--- a/src/qjackctlGraph.cpp
+++ b/src/qjackctlGraph.cpp
@@ -51,6 +51,7 @@
 
 #include <algorithm>
 
+#define _USE_MATH_DEFINES
 #include <math.h>