[Boost-users] Re: boost::unary_traits

From: Matthias Kaeppler (nospam_at_[hidden])
Date: 2005-03-04 16:12:51

Jonathan Turkanis wrote:
> Matthias Kaeppler wrote:
> 
> 
>> > In any event, since you need to
>> > redefine argument_type and result_type yourself, there is no point
>> > inheriting from std::unary_function.
>> >
>>
>>Why? I thought those types are boost::unary_traits specific types? I
>>thought I have to inherit from std::unary_function if I want to create
>>what is called an "Adaptable Unary Function"?
> 
> 
> To define an adaptable unary function, all you need is the member types. One way
> to acquire them is to inherit from unary_function. If you redefine argument_type
> and result_type, inheriting from unary function does no good;in fact, it's
> harmful if the argument_type and result_type don't coincide with the inherited
> versions, since users may only look at the base class list.
> 
> Jonathan

Okay, thanks for clearing that up.

-- 
Matthias Kaeppler