/** 
 * Description: 
 * Author: 
 * Date: 
 */
#include <stdio.h>
#include <stdlib.h>


typedef struct 
{
  int m1i1;
  int m1i2;
  char* m1p1;
} mess_1;

typedef struct 
{
  int m2i1;
  int m2i2;
  long m2l1;
} mess_2;
  
typedef struct
{
  int m_type;
  long m_source;
  union {
    mess_1 m_m1;
    mess_2 m_m2;
  } m_u;
} message;


void print(message *mptr)
{
  printf("\nMessage type: %d\n", mptr->m_type);
  switch( mptr->m_type ) {
  case 1:
    printf("m_type = %d\nm_source = %ld\nm1i1 = %d\nm1i2 = %d\n*m1p1 = %s\n",
	 mptr->m_type, mptr->m_source, 
	 mptr->m_u.m_m1.m1i1, 
	 mptr->m_u.m_m1.m1i2, 
	 mptr->m_u.m_m1.m1p1);
    break;
  case 2:
    printf("m_type = %d\nm_source = %d\nm2i1 = %d\nm2i2 = %d\nm2l1 = %ld\n",
	 mptr->m_type, mptr->m_source, 
	 mptr->m_u.m_m2.m2i1, 
	 mptr->m_u.m_m2.m2i2, 
	 mptr->m_u.m_m2.m2l1);
    break;
  default:
    ;
  }
}

int main(int argc, char *argv[])
{
  message m1 = { 1, 12, {{5, 10, "lock"}} };
  message m2; /* Only the first member of a union can be initialized in the decl. */

  m2.m_type = 2;
  m2.m_source = 14;
  m2.m_u.m_m2.m2i1 = 20;
  m2.m_u.m_m2.m2i2 = 30;
  m2.m_u.m_m2.m2l1 = 500L;

  print(&m1);
  print(&m2);
  printf("size of long = %d\n", sizeof(long));
  return 0;
  
}