Re: [boost] [regex] Clearing failures in regex_regress on Tru64/CXX

From: David Abrahams (dave_at_[hidden])
Date: 2005-07-01 02:48:36

Markus Schöpflin <markus.schoepflin_at_[hidden]> writes:

> Christoph Ludwig wrote:
>
>> On Wed, Jun 29, 2005 at 02:52:12PM +0200, Markus Schöpflin wrote:
>
>>>Christoph Ludwig wrote:
>
>>>>Section 10.5:
>>>>  The standard also specifies that there can be at most one explicit
>>>>  instantiation of a certain template specialization in a
>>>>  program. Furthermore, if a template specialization is explicitly
>>>>  instantiated, it should not be explicitly specialized, and vice versa.
>>>
>>>I can't find anything in the standard (14.7) indicating this.
>
>> OK, I overcame my laziness :-) It is 14.7p5:
>> 
>>   No program shall explicitly instantiate any template more than once, both
>>   explicitly instantiate and explicitly specialize a template, or specialize a
>>   template more than once for a given set of template arguments. 
>>   An implementation is not required to diagnose a violation of this rule.
>> 
>> I admit I find Vandvoorde's and Josuttis' phrasing much easier to grok.
>
> Duh, I read 14.7.2 and 14.7.3 over and over and I completely missed that 
> one. :-(
>
> Hmm, now I'm left wondering how in general to deal with this issue. Would 
> this be legal?
>
> ---%<---
> template <class T>
> struct foo {
>    static T bar() { static T t; return t; }
> };
>
> template<> foo<int>;
> template int foo<int>::bar();
> --->%--
>
> Time to ask the compiler vendor on how to avoid multiple copies of t here, 
> I think.

What happens if you explicitly mark it "inline"?

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com