Why can't templates be declared in a function?

Question

Reading C++ Templates: The Complete Guide and it says

Note that templates cannot be declared in a function

It does not give e

Answer 1

The problem is probably linked to the historical way templates were implemented: early implementation techniques (and some still used today) require all symbols in a template to have external linkage. (Instantiation is done by generating the equivalent code in a separate file.) And names defined inside a function never have linkage, and cannot be referred to outside of the scope in which they were defined.