diff --git a/doc/examples/class_CwiseUnaryOp.cpp b/doc/examples/class_CwiseUnaryOp.cpp
new file mode 100644
index 0000000..a5fcc15
--- /dev/null
+++ b/doc/examples/class_CwiseUnaryOp.cpp
@@ -0,0 +1,19 @@
+#include <Eigen/Core>
+#include <iostream>
+using namespace Eigen;
+using namespace std;
+
+// define a custom template unary functor
+template<typename Scalar>
+struct CwiseClampOp {
+  CwiseClampOp(const Scalar& inf, const Scalar& sup) : m_inf(inf), m_sup(sup) {}
+  const Scalar operator()(const Scalar& x) const { return x<m_inf ? m_inf : (x>m_sup ? m_sup : x); }
+  Scalar m_inf, m_sup;
+};
+
+int main(int, char**)
+{
+  Matrix4d m1 = Matrix4d::Random();
+  cout << m1 << endl << "becomes: " << endl << m1.unaryExpr(CwiseClampOp<double>(-0.5,0.5)) << endl;
+  return 0;
+}