John Maddock a écrit :
Well.... this is one of those "complex" solutions that was suggested last time this was discussed that I've been trying to avoid ;-) I was unable to retrieve the "original" thread about the numeric consatnt so I can't find the roots of the discussion but I guessed it was problematic.
Off the top of my head, the main problems I see are:
* What is the result of 2 * pi? How about 2 * pi * r where r is a real? What I did was assigning to each constant a conversion policy. 2*pi is prolly a double by default, while 2*pi*r is the greatest common real type between double and type of r. * If you mistakenly call a function passing a constant as argument, for example foo(2.0, pi), then if foo is a template you will likely get an inscutable failure very deep inside foo's body (or worse some other function that foo calls). Yes that's the main problem of this solution I think. In my case, the consatnts are alwasy used with "constant" aware function so the problem doesn't appear. * In order to avoid ODR violations I presume the constants have to be defined in an anonymous namespace? Does this cause code bloat simply by #including the constants header? I don't get how ODR if violated in this case. Now I suspect that all of these issues are probably solvable to some degree, it's a question of whether it's worth the hassle, and/or whether the resulting code is likely to turn into a problem to maintain. Yes, as said above I *thought* it was discussed somewhere but wasn't able to retrieve the actual discussion. So everything perfectly fine now that thigns ahve been cleared out ;)
-- ___________________________________________ Joel Falcou - Assistant Professor PARALL Team - LRI - Universite Paris Sud XI Tel : (+33)1 69 15 66 35