IO进程线程day9作业

#ifndef _SEM_H_
#define _SEM_H_
#include<myhead.h>
//信号灯集的申请，初始化信号灯，并返回信号灯集的id
int create_sem(int semcount);

//申请信号灯资源操作  P操作  -1
int P(int semid,int semno);

//释放信号灯资源操作  V操作  +1
int V(int semid ,int semno);

//删除信号灯集
int del_sem(int semid);


#endif

#include<myhead.h>
#include"sem.h"
union semun {
	int              val;    /* Value for SETVAL */
	struct semid_ds *buf;    /* Buffer for IPC_STAT, IPC_SET */
	unsigned short  *array;  /* Array for GETALL, SETALL */
	struct seminfo  *__buf;  /* Buffer for IPC_INFO
								(Linux-specific) */
};

int init_sem(int semid,int i)
{
	int val = -1;
	printf("请输入第%d个的val值:",i);
	scanf("%d",&val);

	union semun su;
	su.val = val;
	if(semctl(semid,i,SETVAL,su) == -1)
	{
		perror("semctl");
		return -1;
	}
}

//信号灯集的申请，初始化信号灯，并返回信号灯集的id
int create_sem(int semcount)
{
	//1、创建key值
	key_t key = ftok("/",'k');
	if(key == -1)
	{
		perror("ftok");
		return -1;
	}
	
	//2、通过key值创建一个信号灯集
	int semid = semget(key,semcount,IPC_CREAT|IPC_EXCL|0664);
	if(semid == -1)
	{
		if(errno == EEXIST)
		{
			semid = semget(key,semcount,IPC_CREAT);
			return semid;
			
		}
		perror("semget");
		return -1;
	}
	//3、给信号灯集中的信号等进行初始化操作
	for(int i =0;i<semcount;i++)
	{
		init_sem(semid,i);
	}
	//4、返回信号灯集的id
	return semid;
	
}

//申请信号灯资源操作  P操作  -1
int P(int semid,int semno)
{
	struct sembuf buf;
	buf.sem_num = semno;
	buf.sem_op = -1;
	buf.sem_flg = 0;
	if(semop(semid,&buf,1) == -1)
	{
		perror("semop P");
		return -1;
	}
	return 0;
}

//释放信号灯资源操作  V操作  +1
int V(int semid ,int semno)
{
	struct sembuf buf;
	buf.sem_num = semno;
	buf.sem_op = 1;
	buf.sem_flg = 0;
	if(semop(semid,&buf,1) == -1)
	{
		perror("semop V");
		return -1;
	}
	return 0;
}

//删除信号灯集
int del_sem(int semid)
{
	if(semctl(semid,0,IPC_RMID,0)== -1)
	{
		perror("semctl aa");
		return -1;
	}
}

#include <myhead.h>
#include "sem.h"
#define SIZE_PAGE 4096
int main(int argc, const char *argv[])
{
	//定义一个变量存放pid
	int pid1 = -1,pid2 = -1;
 
	//1.创建信号灯集
	int semid = create_sem(3);
	if(semid == -1)
	{
		perror("create error");
		return -1;
	}
 
	//创建子进程1
	pid1 = fork();
 
	if(pid1 == 0)
	{
		int count = 0;
		//子进程1
		while(count <5 ) 
		{	
			count++;
			P(semid,0);    //申请0号灯资源
			sleep(1);
			printf("B");
			fflush(stdout);
			V(semid,1);      //释放1号灯资源
		}
 
		//退出子进程1
		exit(EXIT_SUCCESS);
	}else if(pid1 > 0)
	{
		//创建子进程2
		pid2 = fork();
 
		if(pid2 == 0)
		{
			int count = 0;
			//子进程2
			while(count < 5)
			{
				count++;
				P(semid,1);    //申请1号灯资源
				sleep(1);
				printf("C\n");    
				V(semid,2);   //释放2号灯资源
			}
 
			//退出子进程2
			exit(EXIT_SUCCESS);
		}else if(pid2 > 0)
		{
			int count = 0;
			//父进程
			while(count < 5)
			{
				P(semid,2);   //申请2号灯资源
				sleep(1);
				printf("A");
				fflush(stdout);
				V(semid,0);  //释放0号灯资源
				count ++;
			}
			
			//回收子进程
			wait(NULL);
			wait(NULL);
 
			//删除信号灯资源
			del_sem(semid);
 
			return 0;
 
		}else
		{
			perror("fork pid2 error");
			return -1;
		}
	}else
	{
		perror("fork pid1 error");
		return -1;
	}
 
	return 0;
}