Exceptional C++ Style 40 New Engineering Puzzles, Programming Problems, and Solutions

Chapter 7. Why Not Specialize Function Templates?

Difficulty: 8

Although the title of this Item is a question, it could also be made into a statement: This Item is about when and why not to specialize templates.

JG Question

1. What two major kinds of templates are there in C++, and how can they be specialized?

Guru Question

1. In the following code, which version of f will be invoked by the last line? Why?

   template<class T>
   void f(T);
   
   template<>
   void f<int*>(int*);
   
   template<class T>
   void f(T*);
   
   // …
   
   int *p;
   f(p);               // which of the f's is called here?
   

Solution

The Important Difference: Overloading vs. Specialization

It's important to make sure we have the terms down pat, so here's a quick review.

1. What two major kinds of templates are there in C++, and how can ...