Partial Function Template Specialization or Overloading: When Should You Use Which?

Partial Function Template Specialization or Overloading?

In C , it's a common misconception that partial specialization is possible for function templates. However, the C standard only allows full specialization.

Overloading vs. Partial Specialization

The code provided initially:

#include <iostream>

template <typename T1, typename T2>
inline T1 max(T1 const& a, T2 const& b) {
    return a < b ? b : a;
}

template <typename T>
inline T const& max(T const& a, T const& b) {
    return 10;
}

doesn't demonstrate partial specialization but overloading of the max function. Overloading allows multiple functions with the same name but different argument types.

Concept of Partial Specialization

Partial specialization is when a class or function template is specialized for a specific set of template parameters. For classes, this is achieved by providing a specialized template with the same name but fewer parameters. For function templates, partial specialization would involve specifying only a subset of the template parameters, which is currently not allowed by the C standard.

Example of Partial Class Specialization

Partial specialization for classes looks like this:

template <typename T1, typename T2>
class MyClass {
    // ...
};

// Partial specialization: both template parameters have the same type
template <typename T>
class MyClass<T, T> {
    // ...
};

Compiler Extensions

Some compilers, such as Microsoft Visual Studio 2010 Express, may provide partial specialization for function templates as an extension. However, using such extensions compromises code portability, as other compilers may not support them.

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