c - Usage of void pointers across different platforms

Question

I have heard that pointers should first be cast to void to ensure consistency of values across different platforms and should use %p format specifier. Why is it and what exactly are the problems?

int x=100;
int *pi=&x;
printf("value of pi is: %p",(void*)pi);

Answer 1

printf is a variadic function and must be passed arguments of the right types. The standard says %p takes void *.

Implicit cast doesn't take place for variadic functions.

Quoting from N1570 7.21.6.1 The fprintf function

p : The argument shall be a pointer to void. The value of the pointer is converted to a sequence of printing characters, in an implementation-defined manner.