Hello, I've encountered a problem compiling code that uses boost multi_index_container. I'm using both Microsoft Visual Studio 2005 and Apple's gcc 4.0.1. Visual Studio was very picky about how I used namespaces. I finally got it working with the code below. The key to success was the 'using namespace boost::multi_index' line. If I attempted to prefix the members directly, eg. typedef typename boost::multi_index::nth_index_const_iterator<0>::type left_const_iterator; or namespace mi=boost::multi_index; typedef typename mi::nth_index_const_iterator<0>::type left_const_iterator; it would fail to compile. However, when I attempt to compile the same code on Mac OS X using gcc 4.0.1 I get the following errors. Does anyone know why? src.cpp:98:error: wrong number of template arguments (1, should be 2) /boost/boost/multi_index_container_fwd.hpp:46: error: provided for 'template<class MultiIndexContainer, int N> struct boost::multi_index::nth_index_const_iterator' src.cpp:98: error: expected ';' before 'left_const_iterator' src.cpp:99: error: wrong number of template arguments (1, should be 2) /boost/boost/multi_index_container_fwd.hpp:46: error: provided for 'template<class MultiIndexContainer, int N> struct boost::multi_index::nth_index_const_iterator' src.cpp:99: error: expected ';' before 'right_const_iterator' -----code---- using namespace boost::multi_index; 88 template<class A, class B=String> 89 class SimpleBiMap : public multi_index_container< 90 pair<A,B>, 91 indexed_by< 92 ordered_unique<member<pair<A,B>, A, &pair<A,B>::first> >, 93 ordered_unique<member<pair<A,B>, B, &pair<A,B>::second> > 94 > > 95 { 96 public: 97 typedef pair<A,B> mytype; 98 typedef typename nth_index_const_iterator<0>::type left_const_iterator; 99 typedef typename nth_index_const_iterator<1>::type right_const_iterator; 100 101 SimpleBiMap(const mytype init[], int N) { 102 for (int i=0; i<N; i++) { 103 insert(init[i]); 104 } 105 } 106 107 left_const_iterator find(const A &key) const { return get<0>().find(key); } 108 right_const_iterator find(const B &key) const { return get<1>().find(key); } 109 110 left_const_iterator left_end() const { return get<0>().end(); } 111 right_const_iterator right_end() const { return get<1>().end(); } 112 113 const B &operator[](const A &key) const { return get<0>().find(key)->second; } 114 const A &operator[](const B &key) const { return get<1>().find(key)->first; } 115 }; ---code--- Thank you, Dwight Kelly Apago, Inc.