Forward an invocation of a variadic function in C

Question

In C, is it possible to forward the invocation of a variadic function? As in,

int my_printf(char *fmt, ...) {
    fprintf(stderr, \"Calling printf with fmt %         


        

Answer 1

There's no way to forward such function calls because the only location where you can retrieve raw stack elements is in my_print(). The usual way to wrap calls like that is to have two functions, one that just converts the arguments into the various varargs structs, and another that actually operates upon those structs. Using such a double-function model, you can (for example) wrap printf() by initializing the structs in my_printf() with va_start(), and then pass them to vfprintf().