Unnamed namespaces in headers, was [boost] Boost.Threads proposed change: lock constructors

From: Peter Dimov (pdimov_at_[hidden])
Date: 2004-06-29 11:43:17

David Abrahams wrote:
> Michael Glassford <glassfordm_at_[hidden]> writes:
>
>>> Also, going back to the struct technique, do the struct instances
>>> need to be in an anonymous namespace to prevent ODR violations? Just
>>> trying to get my head around the concept.
>>
>> Probably they should be in a separate namespace, though possibly not
>> anonymous.
>
> Anonymous namespaces in header files *cause* ODR violations.  Not sure
> how they can be used to prevent ODR violations.
>
> Peter, are you planning to get the bind placeholders out of the
> unnamed namespace?

I'm not sure how the bind placeholders can cause ODR violations; could you
elaborate?

Anyway, I guess we'll have to migrate to TR1 style placeholders one day, but
this will break existing code.