Neither is defined in any way AFAIK. They aren't even present in Boost.Build. There also not present in Boost.Config, so I would think they aren't touched in any way by Boost code.
...Not that I know what those do, I just know how to do a text search ;-)
Thanks for checking. FYI, _SECURE_SCL, which is 1 by default, turns on the "secure" version of the C/C++ libraries. This version, among other things, includes extra checks in some functions. MSFT claims these checks should not slow down functions but I wanted to know if somebody had noticed a slowdown in boost libraries compiled with this option. As far as _HAS_ITERATOR_DEBUGGING, which is also 1 by default, turns on some extra checks inside STL _in debug mode only_. These checks are pretty heavy, to the point of changing the complexity of STL algorithms. For example, std::lower_bound(it_begin, it_end, val, pred) will execute pred(it_current, val) when appropriate. If _HAS_ITERATOR_DEBUGGING is 1, MSFT calls pred _twice_, once like pred(it_current, val) and once like (val, it_current). This, besides slowing down lower_bound, prohibits the use of a predicate that takes different argument types. Anyway, I think something like this could be in the boost docs, so that users compiling boost libraries in debug mode define it, or at least know of the possible effects. Opinions? Thanks Delfin Rojas