C++ PATCH: PR 20599 (1/3)

[Paolo Carlini]

Joe Buck wrote:

>In any case, we shouldn't accept any extension that isn't rigorously specified:
>if it isn't in a released standard, it should have a rigorous description
>with the same kind of detail that one finds in an official standard.
>
As far as I can see, Doug's variadic templates certainly qualify, from 
this point of view.

For all the reasons explained again by Doug and Joe, I would like to see 
some leeway for that subset of C++0x features which cannot possibly 
result in incompatibilities. At the same time, we must help the users 
with appropriate warnings, and do more disruptive work only in a new branch.

Now I have one specific technical issue: in case, are we sure that 
#pragma  GCC system_header works well also together with templates? I'm 
asking because in the past I certainly saw strange things going on... 
Anyway, if we can make sure the pragma works, then providing now a 
library exploiting some of those features (e.g., variadic templates) 
together with a front-end normally emitting warnings, i.e., not only 
with -pedantic, would be possible and maybe a solution we could agree upon.

Paolo.