Re: [Boost-users] [function_types] comparing arity

Subject: Re: [Boost-users] [function_types] comparing arity
From: Jeff Flinn (Jeffrey.Flinn_at_[hidden])
Date: 2012-03-02 21:05:10

Jeff Flinn wrote:
> Jeff Flinn wrote:
>> I'm trying to come up with the condition for an enable_if condition 
>> based on the function_arity of a signature. The following fails to 
>> compile:
>>
>> bool z
>> = boost::mpl::equal_to
>> < boost::function_types::function_arity<SIG>::value
>> , boost::mpl::int_<3>
>>  >;
> 
> Ok this compiles:
> 
> bool z
> = boost::mpl::equal_to
> < typename boost::function_types::function_arity<SIG>::type
> , boost::mpl::int_<3>
>  >::value;
> 
> But when used in the following fails to compile:
> 
> typename enable_if

Doh!

typename boost::enable_if

> < typename boost::mpl::equal_to
>   < typename boost::function_types::function_arity<SIG>::type
>   , boost::mpl::int_<3>
>   >::type
>  , typename boost::function_types::result_type<SIG>::type
>  >::type

Compiles, links and runs. Time for the bar!

Sorry for the noise.

Jeff