Re: [boost] [function types] cv-qualification on function types

From: Tobias Schwinger (tschwinger_at_[hidden])
Date: 2005-07-08 18:19:16

Peter Dimov wrote:
> Tobias Schwinger wrote:
> 
> [...]
> 
> 
>>>>>   typedef int my_const_function() const;
> 
> 
>>Where do I find it in the standard and/or what should happen in the
>>following two cases?
> 
> 
> Don't know about the standard, but...
> 
> 
>>  template<typename T>
>>  struct remove_member_pointer  { typedef T type; };
>>
>>  template<typename T, typename C>
>>  struct remove_member_pointer< T C::* > { typedef T type; };
>>
>>  remove_member_pointer< my_const_function >::type // <-- case 1
> 
> 
> The specialization doesn't match, because int () const is not of the form T 
> C::*, so the primary template is selected and echoes my_const_function back.

Ooops -- of course! Actually I wanted to write "my_const_mem_fun_ptr" - 
fortunately you applied some intuitive error correction on the fly...

> 
> 
>>  template<typename T, typename C> struct add_member_pointer
>>  { typedef T C::*type; };
>>
>>  class X;
>>
>>  add_member_pointer< my_const_function, X >::type // <-- case 2
> 
> 
> int (X::*) () const. 
 >
> If you pass that to remove_member_pointer, it would 
> give you my_const_function. 
> 

Makes sense.

Would be too great if /all/ compilers behaved this way...

Thanks,

Tobias