The 2nd usage of C Macro

Use function like a variable.

 

#include <stdio.h>

int a = 9;
int *no_p;

int *__number_location() 
{
  no_p = &a;
  return no_p;
}


#define number (*__number_location())

int main()
{
  number = 10;
  printf("number is %d\n", number);
}