ipc.h

抽烟者问题。假设一个系统中有三个抽烟者进程

#include<stdio.h>
#include<stdlib.h>
#include<sys/types.h>
#include<sys/ipc.h>
#include<sys/shm.h>
#include<sys/sem.h>
#include<sys/msg.h>

#define BUFSZ 256

int get_ipc_id(char *proc_file,key_t key);

char *set_shm(key_t shm_key,int shm_num,int shm_flag);

int set_msq(key_t msq_key,int msq_flag);

int set_sem(key_t sem_key,int sem_val,int sem_flag);
int down(int sem_id);
int up(int sem_id);

typedef union semuns{
       int val;
}Sem_uns;

typedef struct msgbuf{
       long mtype;
       char mtext[1];
}Msg_buf;

//吸烟提供者共享缓冲区及其有关的变量
key_t buff_key;
int buff_num;
char *buff_ptr;

//提供者放产品位置的共享指针
key_t pput_key;
int pput_num;
int *pput_ptr;

//三个吸烟者取产品位置的共享指针
key_t cig_get_key,pap_get_key,glu_get_key;
int cig_get_num,pap_get_num,glu_get_num;
int *cig_get_ptr,*pap_get_ptr,*glu_get_ptr;

//提供者有关的信号量
key_t prod_key;
key_t pmtx_key;
int prod_sem;
int pmtx_sem;

//三个吸烟者有关的信号量
key_t cig_key,pap_key,glu_key;
key_t smtx_key;
int cig_sem,pap_sem,glu_sem;
int smtx_sem;

int sem_val;
int sem_flg;
int shm_flg;