Variadic Templates (C++11)

One-Liner

Lets templates accept any number of arguments of any type — the modern, type-safe replacement for C-style variadics (va_list).

Header

No header required (language feature)

Core API Cheat Sheet

Operation	Signature	Description
Type parameter pack	typename... Ts	Accepts zero or more type parameters
Non-type parameter pack	Ts... args	Accepts zero or more non-type parameters
Template template parameter pack	template<typename> class... Ts	Accepts zero or more templates
Parameter pack expansion	args...	Expands the parameter pack into multiple expressions
Parameter pack size	sizeof...(args)	Returns the number of elements in the parameter pack
Fold expression	(args op ...) / (... op args)	C++17, applies an element-wise operation to the pack

Minimal Example

// Standard: C++11
#include <iostream>

template<typename... Ts>
void print(Ts... args) {
    // Use an initializer list to print the arguments one by one, in order
    int dummy[] = {(std::cout << args << " ", 0)...};
    (void)dummy;
}

int main() {
    print(1, "hello", 3.14);
}

Embedded Applicability: Medium

• Can fully replace the unsafe va_list, improving type safety and code maintainability
• Template instantiation causes code bloat (larger binary size), so keep an eye on Flash usage
• A good fit for resource-richer settings (e.g., application processors running Linux); needs careful evaluation on low-end bare-metal MCUs

Compiler Support

GCC	Clang	MSVC
4.3	2.9	TBD

See Also

• cppreference: Parameter packs

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