Hi Neal,
From: Neal Becker I thought to use 'unconstrained', but this isn't really what I need. I have a fixed_pt integer class,
//! signed fixed pt template<int int_bits, int frac_bits, typename base_type=int, typename error_policy=cv::throw_exception<>, typename round_policy=rnd<base_type> > struct fixed_pt : ... typedef typename cv::bounded_int<base_type, min, max,error_policy>::type val_t;
When I want to turn off checking, it seems the thing to do is use an error_policy which ignores the error. I've been using this, which I got from you some time ago:
struct no_error_policy { template <typename V, class C> void operator () (V & old_val, const V & new_val, C &) { old_val = new_val; } };
So I can write: fixed_pt<16,5,int,cv::no_error_policy> f;
Maybe this is a useful addition to the lib, or at least as an example?
OK, now I think I see what you want to do. I don't think using this policy is a good idea for two reasons: - as I've written before, it is not a correct error policy in a general case. It will break the bounded object's invariant (and fire an assertion) if you assign an invalid value; - it will make it harder for the compiler to optimize the unnecessary checks away. What I would suggest is using bounded_int when there is actually a need for error checking, and using unconstrained when there should be no error-checking: struct no_error_checking {}; // a tag to indicate no checks at all template<... typename base_type = int, typename error_policy = cv::throw_exception<> ...> struct fixed_pt { typedef typename if_< is_same<error_policy, no_error_checking >::type, cv::unconstrained<base_type>::type, cv::bounded_int<base_type, min, max, error_policy>::type >::type val_t; Or, if there are no issues with the interface compatibility, you may use the underlying value type directly: typedef typename if_< is_same<error_policy, no_error_checking >::type, base_type, cv::bounded_int<base_type, min, max, error_policy>::type >::type val_t; Hope this helps, Robert