Index: mttroot/mtt/cc/include/useful-functions.hh
==================================================================
--- mttroot/mtt/cc/include/useful-functions.hh
+++ mttroot/mtt/cc/include/useful-functions.hh
@@ -20,10 +20,16 @@
 */
 #else
 #define cast_to_double	static_cast<double>
 using std::pow;
 #endif /* ! __cplusplus */
+
+
+static double pi = M_PI;
+static double Pi = M_PI;
+static double PI = M_PI;
+
 
 static inline double
 max (const double x1, const double x2)
 {
   return cast_to_double ((x1 >= x2) ? x1 : (x1 < x2) ? x2 : 0);