Re: [Boost-users] vc 8 secure stl/runtime and boost

From: Delfin Rojas (drojas_at_[hidden])
Date: 2005-12-14 19:20:58

> 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