A bit of context: * Intel 9.0 has __EDG_VERSION__==304 (under Win32/Linux), whereas prior versions of the compiler have lower values of this macro. * BOOST_FUNCTION_SCOPE_USING_DECLARATION_BREAKS_ADL is defined for __EDG_VERSION__<=303, that is, for all Intel compilers up to (and including) 8.1, under Win32/Linux. * Under Win32, all Intel toolset .jams define the compiler option --arg_dep_lookup, which explicitly enables ADL (disabled by default.) I don't know what the situation of ADL is for Intel under Linux, but in any case this switch is *not* used for that OS. Current RC tests for Intel 9.0 under Linux show the problem listed at http://tinyurl.com/8f5g6 One piece of code where the error pops up is like this #if defined(BOOST_FUNCTION_SCOPE_USING_DECLARATION_BREAKS_ADL) ::boost::multi_index::detail::swap(i1,get<1>(es2)); #else using std::swap; swap(i1,get<1>(es2)); #endif Given the __EDG_VERSION__ number of this compiler, it is the second preprocessor branch that is compiled, and it fails to use the user-supplied global swap() in favor of std::swap(), hence the error. However, this same tests succesfully passes for Intel 9.0 under Win32 (same __EDG_VERSION__ as the Linux case)!! My conclusions: * The fact that the test passes under Intel 9.0 for Win32, for which BOOST_FUNCTION_SCOPE_USING_DECLARATION_BREAKS_ADL is *not* defined, suggests that __EDG_VERSION__<=303 is the right check for setting this macro. * But the same test fails under Intel 9.0 for Linux, which hints at an ADL problem other than that controlled by BOOST_FUNCTION_SCOPE_USING_DECLARATION_BREAKS_ADL. Could it be that Intel compilers under Linux also necessitate the --arg_dep_lookup compiler switch (which is currently not set)? This looks like the only sensible conslusion from the facts described. Thanks and sorry for the long post, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo