Boost C++ Libraries of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

This is the documentation for a snapshot of the master branch, built from commit 493d7c2b6c.


// (C) Copyright Andrew Sutton 2007
// Use, modification and distribution are subject to the
// Boost Software License, Version 1.0 (See accompanying file
// LICENSE_1_0.txt or


#include <boost/property_map/property_map.hpp>

// TODO: This should really be part of the property maps library rather than
// the Boost.Graph library.

namespace boost
// A null property is somewhat like the inverse of the constant
// property map except that instead of returning a single value,
// this eats any writes and cannot be read from.

template < typename Key, typename Value > struct null_property_map
    typedef Key key_type;
    typedef Value value_type;
    typedef void reference;
    typedef boost::writable_property_map_tag category;

// The null_property_map<K,V> only has a put() function.
template < typename K, typename V >
void put(
    null_property_map< K, V >& /*pm*/, const K& /*key*/, const V& /*value*/)

// A helper function for intantiating null property maps.
template < typename Key, typename Value >
inline null_property_map< Key, Value > make_null_property()
    return null_property_map< Key, Value >();