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From: Arkadiy Vertleyb (vertleyb_at_[hidden])
Date: 2007-06-14 12:11:56

"Sebastian Redl" <sebastian.redl_at_[hidden]> wrote
> Arkadiy Vertleyb wrote:
>> "Douglas Gregor" <dgregor_at_[hidden]> wrote
>>> That's fine, so long as the template is not instantiated differently in
>>> different translation units.
>> And, since the instantiation itself is done by the library user, and the
>> library author can't know how it will be done, this technique must be
>> prohibited according to ODR.
> The ODR doesn't prohibit techniques, merely occurrences.
> If the library specializes the template for its types, then it should do
> so in a way that the specialization is visible whenever the type is
> visible. Otherwise, yes, ODR can occur.
> Or, if the library doesn't want to introduce the unavoidable dependency,
> it should document very clearly that, in order to use both this library
> and the library providing the template, the client must include the
> header that provides the specialization.
> But this doesn't make the technique invalid.

I would say that, if your technique, as a library author, can easily lead to
the violation of language rules by your users, even though these users don't
do anything obviously wrong, such technique can be defined as invalid.


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