C - Passing function with unknown params to another function, and calling it -

i'm trying achieve this:

void sum(int a, int b){ printf("result: %d", a+b); }  void callfunc(void (*funct)(...), ...) {      va_list ars;       va_start(ars, funct);      funct(ars);      va_end(ars); }  int main() {      callfunc(sum, 2,3);                return 0; } 

but doesn't work, because of needing of 2 va_lists, funct params , arguments passed. however, if try pass sum function, says:error: invalid conversion 'void (*)(int, int)' 'void (*)(...)'

so how make work old c-style?

you can't that. it's not possible.

the best can (while keeping generic) change funct take va_list, vprintf. won't work purposes.

alternatively, can macro:

#include <stdio.h>  #define call_func(func, ...) func(__va_args__)  void sum(int a, int b){ printf("result: %d", a+b); }  int main() {      call_func(sum, 2, 3);                return 0; }