Added LocalFunction examples.

[SVN r77021]

example/expensive_copy_lambda.cpp

@@ -0,0 +1,40 @@
+
+// Copyright (C) 2009-2012 Lorenzo Caminiti
+// Distributed under the Boost Software License, Version 1.0
+// (see accompanying file LICENSE_1_0.txt or a copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+// Home at http://www.boost.org/libs/local_function
+
+#include <boost/config.hpp>
+#ifndef BOOST_NO_LAMBDAS
+
+#include <iostream>
+#include <cassert>
+
+//[expensive_copy_lambda
+struct n {
+    int i;
+    n(int _i): i(_i) {}
+    n(n const& x): i(x.i) { // Some time consuming copy.
+        for (unsigned i = 0; i < 10000; ++i) std::cout << '.';
+    }
+};
+
+int main(void) {
+    n x(-1);
+
+    auto f = [x]() {        // Problem: Expensive copy, but if bind
+        assert( x.i == -1); // by `&x` then `x` is not constant.
+    };
+    f();
+
+    return 0;
+}
+//]
+
+#else // NO_LAMBDAS
+
+int main(void) { return 0; } // Trivial program.
+
+#endif // NO_LAMBDAS
+