Passing variadic parameters from one function to another

Question

I am calling a function firstFunction and passing it variadic arguments (const char* fmt, ...) : I would like to execute some calculations here and then pass the parameters to another function, secondFunction that has (const char* fmt, ...) as input arguments.

void firstFunction(const char* fmt, ...)
{
 //does some pre-condition stuff

//calls secondFunction (how?)
}

void secondFunction(const char* fmt, ...)
{
//prints the input parameters in a va_list using vsnprtinf
}

What is the C++ syntax to pass variadic arguments from a function to another?

EDIT 1: I can't use templates, since I would like these functions to be a definition of pure virtual functions declaration.

https://stackoverflow.com/questions/36881533/passing-va-list-to-other-functions — MadScientist, Jan 16 '20 at 09:15
Note: a *parameter pack* only occurs in variadic templates, this is a C-style varags. — Quentin, Jan 16 '20 at 09:21

score 4 · Accepted Answer · answered Jan 16 '20 at 09:20

4

That's a variadic paramater, not a parameter pack. In c++ you would write:

    template <class... Args>
    void firstFunction(const char* fmt, Args&&... a) {
        secondFunction(fmt, std::forward<Args>(a)...);
    }

answered Jan 16 '20 at 09:20

christianO

167
11

You're right, question corrected – EagleOne Jan 16 '20 at 09:21

Passing variadic parameters from one function to another

1 Answers1