Re: [boost] [swap] End-user allowed to add overloads to boost namespace?

From: Michael Marcin (mike.marcin_at_[hidden])
Date: 2008-07-31 13:05:55

Niels Dekker - mail address until 2008-12-31 wrote:
> Joseph Gauterin wrote:
>> Am I correct in thinking that it's permissible to provide a template
>> specialization of a function in namespace std but not an overload?
> 
> Yes, you are.  :-)  According to both the current C++ Standard and the 
> latest Working Draft.  The Draft 
> www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2691.pdf says at 
> 17.4.3.1.1, Namespace std [namespace.std]:
> 
>  "The behavior of a C++ program is undefined if it adds declarations or 
> definitions to namespace std or to a namespace within namespace std 
> unless otherwise specified. A program may add a template specialization 
> for any standard library template to namespace std only if the 
> declaration depends on a user-defined type of external linkage and the 
> specialization meets the standard library requirements for the original 
> template."
> 

Speaking of swap, ADL, and the next standard...

I remember reading or hearing a long time ago that in C++0x it is an 
error to call std::swap(x,y) directly and you have to do using 
std::swap; swap(x,y);. This seems very unfortunate especially since 
boost can get us ADL swap without that in C++03. Does anyone know if 
this is still true?

Thanks,

Michael Marcin