how to use a dynamic function parameterlist in a function call hierarchy

[mpinkim]

hi,

i have a question about how to use a dynamic parameter list
as in the example required.


int func2(int a,...)
{
//her i will use all the parmeters passed to the func1 function
va_list ap
va_start(ap,a);
do
{
a=(int)va_arg(ap,int);
//=> a=1,a=2,a=3,a=4,a=5;
}while(a!=0);
va_end(ap);
}

int func1(int a,...)
{
func2(a,??????)
}

int main()
{
func1(1,2,3,4,5);
}

my problem is va_list can not be used.
has anyone a idea?

[m4ster r0shi]

You could pass vectors of (const) int pointers to your functions.

[stravant]

Avoid using va_arg at all costs, there's much better, safer ways to do it. If in the end you really have to use it then you've probably made a bad design choice somewhere.

If all the args are the same type just pass them in a collection of some kind as master roshi pointed out.

[mpinkim]

thnx for your ideas. But this solutions are not usable so far i know, because i'm trying
to overload the linux libc library and there especially the functions
open and ioctl (see in /usr/include/unistd.h) use a dynamic parameterlist. So i need to handle
this. Because if my function should be used instead of the origin function
it need to supply the same function signature otherwise it will not be used.

[m4ster r0shi]

Oh, that's a really crappy situation :/ The best solution I can think now is to write loads of overloads for your function, sort of like this:

int my_func(int a)
{
    return lib_func(a);
}

int my_func(int a, int b)
{
    return lib_func(a,b);
}

//etc... 

EDIT: Now that I re-read your post, I think that maybe that's not what you're looking for... Could you explain a bit more? Are your functions wrappers for the library functions? Who is going to call your functions?