Added LocalFunction examples.

[SVN r77021]

example/const_block_err.cpp

@@ -0,0 +1,20 @@
+
+// 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 "const_block.hpp"
+#include <cassert>
+
+int main(void) {
+    //[const_block
+    int x = 1, y = 2;
+    CONST_BLOCK(x, y) { // Constant block.
+        assert(x = y);  // Compiler error.
+    } CONST_BLOCK_END
+    //]
+    return 0;
+}
+