Re: [Boost-users] How to use mpl::count and function_types

Subject: Re: [Boost-users] How to use mpl::count and function_types
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2011-11-25 02:40:20

AMDG

On 11/23/2011 09:29 AM, Allan Nielsen wrote:
> I'm trying to count the number of parameters in a function-type:
> 
>     cout << boost::mpl::count< boost::function_types::parameter_types<
> void() > >::value << endl;
>     cout << boost::mpl::count< boost::function_types::parameter_types<
> void(int) > >::value << endl;
>     cout << boost::mpl::count< boost::function_types::parameter_types<
> void(int, int) > >::value << endl;
> 
> This prints:
> 0
> 0
> 0
> 
> I would have expected:
> 0
> 1
> 2
> 
> What have I done wrong?
> 

What you want is mpl::size.  mpl::count
takes two arguments and return the
number of elements equal to the second
argument (like std::count).

In Christ,
Steven Watanabe