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Why Borland config doesn't have BOOST_NO_ARGUMENT_DEPENDENT_LOOKUP defined?

In my experience it doesn't ADL at least up to 5.6.4 (when I tried)

There may be corner cases that fail (no idea what they may be though, as I've never been hit by them), but mostly it certainly does work, and passes the trivial test in libs/config/test/boost_no_arg_dep_lookup.ipp.

Did you tried a test with operator<<? This is primary target area for ADL, isn't it? Gennadiy

template<typename T> struct abc{};

namespace foobar{

struct A {};

void operator<<( abc<A> const&, char) {}

}

void test() { abc<foobar::A> t;

t << '0'; }

This code compiles by most compilers (including online Cameau), but Borland fails it.

Thanks for the test case, I must admit until very recently I hadn't realised that this kind of ADL (based on introspection of template arguments) was supposed to work at all. I would rather not turn off all ADL support for Borland, because most cases do actually work (for example ADL of swap overloads, and finding of operators that does not involve template argument introspection works), so I think we have two choices: 1) define a new config macro. 2) use BOOST_WORKAROUND if this problem hits you. If the problem is limited to Borland C++ then I vote for (2) at present, but you can always change my mind ;-) John.