Does the GotW #101 “solution” actually solve anything?

Question

First read Herb\'s Sutters GotW posts concerning pimpl in C++11:

• GotW #100: Compilation Firewalls (Difficulty: 6/10)

• GotW #101: Compilation

Answer 1

You are correct; the example seems to be missing an explicit template instantiation. When I try to run the example with a constructor and destructor for widget::impl on MSVC 2010 SP1, I get a linker error for pimpl::pimpl() and pimpl::~pimpl(). When I add template class pimpl;, it links fine.

In other words, GotW #101 eliminates all boilerplate from GotW #100, but you need to add an explicit instantiation of the pimpl<...> template with the implementation of the pimpl impl. At least with #101 the boiler plate you need is straightforward.