What are the automatic type promotions of variadic function arguments?

Question

Consider the following code snippet:

#include 
#include 

void display(int num, ...) {
    char c;
    int j;
    va_list ptr;         


        

Answer 1

another case that the others forgot to mention are pointer types, critical is NULL in particular. Since this could expand to 0 or (void*)0 (or some other weird things) you will not know if the compiler puts an int or a void* in the list. Since these can have different width, this can lead to annoying bugs.