13 Templates [temp]

13.7 Template declarations [temp.decls]

13.7.7 Function templates [temp.fct] General [temp.fct.general]

A function template defines an unbounded set of related functions.
[Example 1:
A family of sort functions might be declared like this: template<class T> class Array { }; template<class T> void sort(Array<T>&);
— end example]
A function template can be overloaded with other function templates and with non-template functions ([dcl.fct]).
A non-template function is not related to a function template (i.e., it is never considered to be a specialization), even if it has the same name and type as a potentially generated function template specialization.138
That is, declarations of non-template functions do not merely guide overload resolution of function template specializations with the same name.
If such a non-template function is odr-used in a program, it must be defined; it will not be implicitly instantiated using the function template definition.