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

While using va_arg the char is promoted to int. There are other types(the list given by @R..) which are promoted.

so in order to read it as a char you have to do typecast.

like: c = (char) va_arg(ap, int);

for the complete example please see:

http://en.cppreference.com/w/cpp/language/variadic_arguments