Re: [Boost-Users] How to pass result of boost::bind to arg of template function ?

From: Douglas Gregor (gregod_at_[hidden])
Date: 2002-10-31 16:55:38

On Thursday 31 October 2002 01:22 pm, hugo duncan wrote:
> Is this possible? if so what signature should the function have ?
>   //! this works fine passing a boost::function object
>   template <class ReturnType>
>   void add(const boost::function1<ReturnType,ObjectType>& arg)
>   {
>     boost::function1<ReturnType,ObjectType> fn_obj=arg;
>   }

Generally speaking, it's not useful to have any of the template arguments to a 
Boost.Function object deduced, because it won't work the way you want it to. 

>   //! this should work when passed the result of a boost::bind
>   template <class ReturnType>
>   void add(?what goes here? & arg)
>   {
>     function1<ReturnType,ObjectType> fn_obj(arg);
>   }
> };

You could take the function object as a template paramter and extract its 
result_type:

template<typename F>
void add(F arg)
{
  typedef typename F::result_type ReturnType;
  function1<ReturnType,ObjectType> fn_obj(arg);
}

        Doug