/*
 * Illustrate setting up a mutex
 * New File Mar 23,1989
 * Author   Jerry LeVan
 *
 */
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <errno.h>

#define COUNT	1		/* How many we are going to create */
#define PERM	0666	/* all can read write */
#define KEY		'JHL '	/* our key */

main()
{
  int id;
  int result;
  /*
  struct sembuf {
	short sem_num;
	short sem_op;
	short sem_flag;
  } op[1];

  */
  struct sembuf op[1];
  id = semget(KEY,0,0);
  printf("status of get key = %d\n",id);
  if(id == -1) {perror("Bad Semaphore ID fetch"); exit();}

  /* initialize the op data structure */
  op[0].sem_num = 0;		/* the first one */
  op[0].sem_op = 1;			/* add 1 now */
  op[0].sem_flg = 0;		/* no options */

  /* now try to  modify the semaphore */
  result = semop(id,op,1);
  if(result == -1){ perror("Bad Signal"); exit();}
  printf("Set semaphore\n");

 }