Index: mttroot/mtt/cc/include/useful-functions.hh
==================================================================
--- mttroot/mtt/cc/include/useful-functions.hh
+++ mttroot/mtt/cc/include/useful-functions.hh
@@ -7,42 +7,58 @@
 #else
 #define inline			// strip from pre-processed file
 #define class_t double
 #endif // __CPLUSPLUS
 
+#ifndef MTT_UNUSED
+#ifdef __GNUC__
+#define MTT_UNUSED __attribute__ ((unused))
+#else
+#define MTT_UNUSED
+#endif // __GNUC__
+#endif // MTT_UNUSED
 
 // == Template functions ==
 
-static inline class_t
+static inline class_t max (const class_t &x1, const class_t &x2) MTT_UNUSED;
+static inline class_t min (const class_t &x1, const class_t &x2) MTT_UNUSED;
+static inline class_t sign (const class_t &x) MTT_UNUSED;
+
+class_t
 max (const class_t &x1, const class_t &x2)
 {
   return ((x1 >= x2) ? x1 : (x1 < x2) ? x2 : 0);
 }
 
-static inline class_t
+class_t
 min (const class_t &x1, const class_t &x2)
 {
   return ((x1 <= x2) ? x1 : (x1 > x2) ? x2 : 0);
 }
 
-static inline class_t
+class_t
 sign (const class_t &x)
 {
   return ((x > 0) ? +1 : (x < 0) ? -1 : 0);
 }
 
 
 // == Octave functions ==
 
-static inline Matrix
+static inline Matrix ones (const int r = 1, const int c = 1) MTT_UNUSED;
+static inline ColumnVector nozeros (const ColumnVector v0, const double tol = 0.0) MTT_UNUSED;
+static inline ColumnVector zeros (const int r) MTT_UNUSED;
+static inline Matrix zeros (const int r, const int c) MTT_UNUSED;
+
+Matrix
 ones (const int r = 1, const int c = 1)
 {
   Matrix m (r, c, 1.0);
   return m;
 }
 
-static inline ColumnVector
+ColumnVector
 nozeros (const ColumnVector v0, const double tol = 0.0)
 {
   ColumnVector v (v0.length ());
   register int i, j;
   for (i = j = 0; i < v.length (); i++)
@@ -59,20 +75,20 @@
     {
       return (v.extract (0, --j));
     }
 }
 
-static inline ColumnVector
+ColumnVector
 zeros (const int r)
 {
   ColumnVector v (r, 0.0);
   return v;
 }
 
-static inline Matrix
+Matrix
 zeros (const int r, const int c)
 {
   Matrix m (r, c, 0.0);
   return m;
 }
 
 #endif // HAVE_USEFUL_FUNCTIONS_HH