In the previous article I have shown you how variadic templates can be a type-safe alternative to va_arg macros in designing the variadic functions. Today I want to show you a few techniques of variadic templates, that can be found in many codebases.
In the previous article, we have seen an old C-style way of defining the variadic functions – via va_args macros. We have also learned their weaknesses: runtime cost, strict contract between caller and the callee and lack of type safety. Not to mention the problem of default type promotion!
Fortunately, standards committee thought this through and equipped us in C++11 with variadic templates. Let’s check them out.
va_args and friendsFrom time to time there is a need to write a function, that accepts an unspecified number of arguments. In C++ we have
multiple ways of handling this depending on the context, use case and available language features. But the oldest and
still most commonly used mechanism is the va_arg.
You think nothing can surprise you? Let’s bet.