#include <sys/types.h>

extern int errno;
extern char *sys_errlist[];

#define NUM_BARBERS 1
#define NUM_CUSTOMERS 20
#define NUM_CHAIRS 5

#define MUTEXKEY ((key_t) 79231L)
#define CUSTOMERSKEY ((key_t) 79232L)
#define BARBERSKEY ((key_t) 79233L)
#define SHMKEY   ((key_t) 79234L)

typedef struct common_data {
  int waiting;
  pid_t chairs[NUM_CHAIRS];
} CDATA;