Re: [boost] [constrained_value] need help with runtime error

Subject: Re: [boost] [constrained_value] need help with runtime error
From: Gordon Woodhull (gordon_at_[hidden])
Date: 2008-12-10 15:48:49

On Dec 10, 2008, at 2:57 PM, Neal Becker wrote:
> // template<typename V, typename C, typename E>
> // cv::constrained<V,C,E> & operator- (cv::constrained<V,C,E> c) {
> //   V tmp (c.value());
> //   c = -tmp;
> //   return c;
> // }
>
>
> int main() {
>  int min = -200;
>  int max = 200;
>  val_t init (10, constraint_type (min, max));
>  val_t neg_x(-init);
>
> If the above operator overload is uncommented, then it does not  
> throw on the last line above, but it STILL throws on the original  
> vector operation:
>
> ublas::vector<val_t> v (10, init);
> ublas::vector<val_t> w = -v;
>
> I can't figure out why the ublas scalar_negate doesn't use my  
> operator-.

I think that operator would have to be in the constrained_value  
namespace for ADL to find it when compiling in the ublas namespace; no  
ADL is necessary when you define the overload in the current namespace.

Gordon