Passing std::vector items to variadic function

Question

I\'m using gcc 4.6. Assume that there is a vector v of parameters I have to pass to a variadic function f(const char* format, ...).

One approach of doing this is:

Answer 1

There's a "Creating a fake va_list" section at http://cocoawithlove.com/2009/05/variable-argument-lists-in-cocoa.html. It's for Cocoa, but you might be able to find something on the net for GCC.

Then, I'm guessing you'd do something like this:

#include 
#include 
#include 
#include 
using namespace std;

struct my_list {
   unsigned int gp_offset;
   unsigned int fp_offset;
   void *overflow_arg_area;
   void *reg_save_area;
};

void f(const char* format, ...) {
    va_list args;
    va_start (args, format);
    vprintf (format, args);
    va_end (args);
}

void test(const vector& v) {
    string fs;
    for (auto i = v.cbegin(); i !=v.cend(); ++i) {
        if (i != v.cbegin()) {
            fs += ' ';
        }
        fs += "%i";
    }
    my_list x[1];
    // initialize the element in the list in the proper way
    // (however you do that for GCC)
    // where you add the contents of each element in the vector 
    // to the list's memory
    f(fs.c_str(), x);
    // Clean up my_list
}

int main() {
    const vector x({1, 2, 3, 4, 5});
    test(x);
}

But, I have absolutely no clue. :)