Re: [boost] [ptr_container] trunk has problems with multiple definitions of xml_names with multiple TUs

From: David Abrahams (dave_at_[hidden])
Date: 2007-11-07 18:29:36

on Wed Nov 07 2007, Steven Watanabe <steven-AT-providere-consulting.com> wrote:

> AMDG
>
> Michael Marcin <mmarcin <at> method-solutions.com> writes:
>
>> 
>> namespace boost
>> {
>>      namespace ptr_container_detail
>>      {
>>          const char* const count  = "count";
>>          const char* const item   = "item";
>>          const char* const first  = "first";
>>          const char* const second = "second";
>>      }
>> }
>> 
>
> Alas, that only replace one form of ODR violation
> with more subtle one.
>
> static const char* count  = "count";
>
> void foo(const char*);
> inline void bar() {
>     // ODR violation here.  count refers to
>     // different objects in different translation
>     // units.  (See section 3.2/5 of the standard.)
>     foo(count);
> }

  template <int = 0>
  struct count
  {
      static char const* const s;
  };

  template <int n>
  char const* const count<n>::s = "count";

  inline void bar()
  {
      foo(count<>::s);
  }

HTH,
-- 
Dave Abrahams
Boost Consulting
http://www.boost-consulting.com