Calling function with variable arguments having a QStringList

[fanoOne]

Hy to all I have a GUI application that at work we use to test the creations of Qt Widget itself, for example I have a dialog to create a QMessageBox with favourited properties icon, title, message and button of Qt or custom (you write the text on a list).

All this data are send using a json and the buttons are memorized in QStringList, I have a C function that creates the json, that normally it would called in C but now I want to call in C++, but how convert the QStringList in the "..." (va_list de facto?).

This is the prototype of the function that I want use:

@
void messagebox(json_object **json, char *iconType, char *title, char msg, int showTime, ...
/ char *btn1, char *btn2, ... */ );
@

I cannot change the signature of the function to use a QStringList as it have to be used by a plain C application...

I have found a solution that in Windows XP works, but, obviusly is not really portable:

@
void foo(int n, va_list args)
{
int i = 0;

printf("[foo] n is %d and i is %d\n", n, i);

for (; i != n; ++i)
    printf("'%s'\n", va_arg(args, char *));

printf("I'm here... safe!\n");

}

int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);

QStringList args = a.arguments();

QVector<char *> v;

// It works but I need to allocate memory as QString::toAscii().data() is not saved in 'v' I don' know why!
foreach (QString a, args) {
    //char str[strlen(a.toAscii().data()) + 1];
    char *str = strdup(a.toAscii().data());

    //strcpy(str, a.toAscii().data());
    printf("adding to v: '%s'\n", a.toAscii().data());
    v << str;
}

foo(args.count(), reinterpret_cast<va_list>((v.data())));

// Now I need to free() str  in v or not? If it was a real function and not main() I has a memory leak here or not?
return 0;

}
@

As you could see it is a Kludge it incredibly works as, at least in Windows, va_list is, in reality a char *, I'm unsure on Linux (where I have to do this tomorrow). So I pass all the strings one after another to the "foo" function...

At least I'd like to use a vector of QString to avoid the allocation of memory but I cannot find a way, data() in this case would be what a QString? Or QString *? Or a QString[]?

By the way if my PM see that code probably he will kill me so I'm asking to you there's a more portable solution in Qt to this problem?

For example supposing that could be happy with max 32 buttons MOC could automate the scripture of code as this:

@
QStringList buttons;

switch(buttons) {
case 0: // We have no buttons so I could call messagebox() w/o the last arg
messagebox(json_object **json, char *iconType, char *title, char *msg, int showTime);
break;

case 1: // We have only one buttons simple is the first element of the list...
   messagebox(json_object **json, char *iconType, char *title, char *msg, int showTime, buttons[0]);
   break;

case 2: /* 2 buttons they're in index 0 and 1 */
messagebox(json_object **json, char *iconType, char *title, char msg, int showTime, buttons[0], buttons[1]);
break;
.... / 3-4-5-6-7-... buttons */
case 31:
messagebox(json_object **json, char *iconType, char *title, char *msg, int showTime, buttons[0], buttons[1], buttons[2], buttons[3], buttons[4], buttons[5], [...], buttons[31]);
break;
}
@

What do you think? Is this possible?

Thanks for your attention...