Re: [Boost-users] Assertions doesn't work!

Kiuhnm writes:

I'm using MSVC8 (2005) with Boost 1.33.1. The code at the end of this post should cause the compiler to print out something like this (GCC):

conversion from 'mpl_::failed ****************(factorial >::FACTORIAL_of_NEGATIVE_NUMBER::****************) (mpl_::int_<-5>)' to non-scalar type 'mpl_::assert<false>' requested.

but I obtain something completely different. It seems that the compiler continues to evaluate the factorial (-1, -2, -3, ...) ignoring the assertions. Since the template expansion is quite "complex", the compiler fails and prints out:

--- fatal error C1202: recursive type or function dependency context too complex

c:\boost\include\boost-1_33_1\boost\mpl\aux_\preprocessed\plain\times.hpp(60) : see reference to class template instantiation 'factorial<N>' being compiled with [ N=boost::mpl::int_<-88> ] ---

What's wrong?

The details of how a compiler does template instantiation are implementation-dependent. It may be instantiating all the base classes before instantiating all the bodies. Try not using metafunction forwarding. -- Dave Abrahams Boost Consulting www.boost-consulting.com