What's the right way to specialize a template when using “extern template”?

Question

I am hoping someone can point out the correct way to specialize a method in a template class while using \"extern template class\" and \"template class\" for explicit instan

Answer 1

Adding this answer to address the question in the title (template instantiation, and not necessarily template method instantiation).

This much resembles function declaration/definition.

• Explicit instantiation declaration: extern template class is a declaration and should generally go in the header.
• Explicit instantiation definition: template class is a definition and should generally go in the cpp.
• No code is generated in object files following the declaration.
• Code is generated in the object file of the cpp that contained the definition.
• Without explicit instantiation, implicit instantiation will take place when the template is actually used. This will happen in every compilation unit (object file) that uses the template.
• Implicit instantiation won't take place if a declaration was encountered. This is the gist of this mechanism - avoid object code duplication caused by implicit instantiation that happened because the compiler didn't trust that there's a single compilation unit in charge of instantiating the template.

More info here.