Create va_list dynamically

Question

I have a function

void foo(int cnt, va_list ap);

I need to use it, but requirement is quite strict, number of va_list vary an

Answer 1

If the number of elements in the list is limited, I would go for manual dispatch depending on the number of elements.

void call_foo(int count, ...) {
    va_list args;
    va_start(args, count);
    foo(count, args);
    va_end(args);
}

switch (contacts.count()) {
    case 0: return call_foo(contacts.count());
    case 1: return call_foo(contacts.count(),
                            contacts.at(0)->getName());
    case 2: return call_foo(contacts.count(),
                            contacts.at(0)->getName(),
                            contacts.at(1)->getName());
    case 3: return call_foo(contacts.count(),
                            contacts.at(0)->getName(),
                            contacts.at(1)->getName(),
                            contacts.at(2)->getName());
    default: /* ERROR HERE, ADD MORE CASES */ return call_foo(0);
}