C 11: Function Aliasing
In C , the using keyword can be used to create an alias for a class. However, the same functionality is not directly available for functions. This article explores the question of whether function aliasing is possible and provides a solution using perfect forwarding.
Objective:
To determine if it is possible to create an alias for a function in C and, if so, to find the cleanest method to accomplish this.
Problem Statement:
Consider the following code:
<code class="cpp">namespace bar { void f(); }</code>
We would like to create an alias named g for the function bar::f. However, the following attempt results in an error:
<code class="cpp">using g = bar::f; // error: ‘f’ in namespace ‘bar’ does not name a type</code>
Solution:
To create a function alias, we can use a combination of templates and perfect forwarding. Here is an example of how this can be achieved:
<code class="cpp">template <typename... Args> auto g(Args&&... args) -> decltype(f(std::forward<Args>(args)...)) { return f(std::forward<Args>(args)...); }</code>
This solution works by creating a generic template function that takes any number of arguments. It then forwards these arguments to the original function f using perfect forwarding. This ensures that the called function receives the arguments in their original form, regardless of any type conversions or pointer dereferences that may have been applied to the alias.
Note:
This solution also works for overloaded functions and function templates, ensuring that the correct function is called based on the arguments provided.
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