Re: Explicite Template Instantiation and Inline

[Paul Pluzhnikov]

tthunder@gmx.de writes:

> Could anyone tell me, why g++ cannot link in this case:

Because it is invalid?

> All other compilers I tried had no problems with this piece of code.

They did? 

The only compiler I can link your code with is Sun CC (11 and 12)
and IBM xlC.

All other compilers (VC6, 8, HP aCC), Intel icc -- fail with
unresolved `void doFunc<bool>()'.

> The member function "notUsed()" is declared "inline". However, the
> explicit template instantiation is implementing it.

It isn't implementing anything. It is asking the compiler to provide
instantiations of all foo<bool>::* methods, which compilers other
than xlC and SunCC oblige to do, introducing the unresolved symbol.

> The above construct helped me avoiding some terrible workarounds. What
> can I do to still use this way of implementation?

You didn't tell what problem this helped you avoid, but if you
want to instantiate foo<bool>::notUsed(), then you must provide
doFunc<bool>() (in this, or some other compilation unit).

> I had a look at some compiler switches like
> "-fno_implement_inlines"... but no, that doesn't work.

Of course it doesn't work. How do you expect the compiler to come
up with body for doFunc<bool>() if you didn't supply one?

BTW, the only reason SunCC and xlC are able to link this is because
they ignore your explicit instantiation request (i.e. it's a bug
in the compiler -- they should have failed as well).

Cheers,
-- 
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