acces parent-struct fields from a child-struct [compilation: gcc -W -Wall -Wextra -std=c89 -fms-extensions polymorphism.c]

polymorphism.c

#include <stdio.h>

struct poly_parent
{
  int a;
  char b;
  void *c;
};

struct poly_child
{
  struct poly_parent;
  short d;
};

int main()
{
  struct poly_child test;

  test.a = 42;
  test.d = 21;
  printf("%d %d\n", test.a, test.d);
  return (0);
}