Re: [boost] [result_of] const-qualified function?

From: Peter Dimov (pdimov_at_[hidden])
Date: 2007-01-26 18:32:24

shunsuke wrote:
> Hi, gurus.
> 
> I have one question about 'result_of':
> 
> 
> template<class F>
> struct forward
> {
>    template<class A>
>    // typename boost::result_of<F(A&)>::type // (1)
>    typename boost::result_of<F const(A&)>::type // (2)
>    operator()(A& a) const
>    {
>        return m_f(a);
>    }
> 
>    explicit forward(F f) : m_f(f)
>    { }
> 
> private:
>    F m_f;
> };
> 
> 
> (1) or (2).. which is right?

(2) is right because m_f is const in operator().

> In fact, (2) fails to compile if 'F' is a function pointer type;
> because const function-pointer specialization is missing.

This is a bug in boost::result_of.