11.14 作业

#ifndef _SEM_H_
#define _SEM_H_

//声明一个创建信号灯集并初始化函数
int init_sem(int semnum);

//声明一个P操作函数
int P(int semid,int semno);

//声明一个V函数
int V(int semid,int semno);

//声明一个删除信号灯集的函数
int del_sem(int semid);

#endif

#include
union semun {
	int val;
	struct semid_ds *buf;
	unsigned short *array;
	struct seminfo *__buf;
};
int set_semno_value(int semid,int semno,int semval)
{
	//定义共用体
	union semun us;
	us.val = semval;
	//调用semctl对灯光进行初始化
	if(semctl(semid,semno,SETVAL,us) == -1){
		perror("semctl error");
		return -1;
	}
	return 0;
}
//创建信号灯集并初始化函数的定义
int init_sem(int semnum)
{
	//1、创建key值
	key_t key;
	if((key = ftok("/",'t')) == -1){
		perror("ftok error");
		return -1;
	}
	//2、创建信号灯集
	int semid;
	if((semid = semget(key,semnum,IPC_CREAT|IPC_EXCL|0664)) == -1){
		if(errno == EEXIST){
			semid = semget(key,semnum,IPC_CREAT|0664);
			return semid;
		}else{
			perror("semget error");
		}
		return -1;
	}

	//3、给信号灯集进行初始化
	for(int i=0;i

#include 
#include"sem.h"
int main(int argc, const char *argv[])
{
	//打开信号灯集
	int semid = init_sem(4);
	//创建key值
	key_t key;
	if((key = ftok("/",'k')) == -1){
		perror("ftok error");
		return -1;
	}
	//创建共享内存
	int shmid;
	if((shmid = shmget(key,4096,IPC_CREAT|0664)) == -1){
		perror("shmget error");
		return -1;
	}
	//映射内存
	char *addr = NULL;
	if((addr = shmat(shmid,NULL,0)) == (void*)-1){
		perror("shmat error");
		return -1;
	}
	//定义一个进程号，创建子进程
	pid_t pid;
	pid = fork();
	if(pid < 0){
		perror("fork error");
		return -1;
	}else if(pid == 0){
		//子进程等待3号资源，释放四号资源
	while(1){
		P(semid, 2);
		printf("请输入>>");
		fgets(addr,4096,stdin);
		addr[strlen(addr)-1] = '\0';
		V(semid,3);
		if(strcmp(addr,"quit") == 0){
			break;
		}
		exit(EXIT_SUCCESS);
	}
	}else{
		//父进程等待二号资源，释放一号资源
		while(1){
		P(semid,1);
		printf("共享内存中的数据为:%s\n",addr);
		V(semid,0);
		if(strcmp(addr,"quit") == 0){
			break;
		}
		}
		wait(NULL);
		exit(EXIT_SUCCESS);
	}
	//取消映射
	if(shmdt(addr) == -1){
		perror("shmdt error");
		return -1;
	}
	return 0;
}

#include 
#include"sem.h"
//定义共用体
union semun{
	int val;
	struct semid_ds *buf;
	unsigned short *array;
	struct seminfo *__buf;
};
int main(int argc, const char *argv[])
{
	//打开信号灯集
	int semid = init_sem(4);
	//创建key值
	key_t key;
	if((key = ftok("/",'k')) == -1){
		perror("ftok error");
		return -1;
	}

	//创建共享内存
	int shmid;
	if((shmid = shmget(key,4096,IPC_CREAT|0664)) == -1){
		perror("shmget error");
		return -1;
	}

	//映射内存
	char *addr = NULL;
	if((addr = shmat(shmid,NULL,0)) == (void*)-1){
		perror("shmat error");
		return -1;
	}

	//创建进程号，创建子进程
	pid_t pid;
	pid = fork();
	if(pid < 0){
		perror("fork error");
		return -1;
	}else if(pid == 0){
		//子进程等待四号资源，释放三号资源
		union semun us;
		us.val = 1;
		semctl(semid,3,SETVAL,us); //初始化四号资源
		while(1){
		P(semid, 3);
		printf("请输入>>");
		fgets(addr,4096,stdin);
		addr[strlen(addr)-1] = '\0';
		V(semid,2);
		if(strcmp(addr,"quit") == 0){
			break;
		}
		exit(EXIT_SUCCESS);
		}
	}else{
		//父进程等待一号资源，释放二号资源
	while(1){
		P(semid,0);
		printf("共享内存中的数据为:%s\n",addr);
		V(semid,1);
		if(strcmp(addr,"quit") == 0){
			break;
		}
	}
	wait(NULL);
	exit(EXIT_SUCCESS);
	}

	//取消映射
	if(shmdt(addr) == -1){
		perror("shmdt error");
		return -1;
	}

	//删除共享内存
	if(shmctl(shmid, IPC_RMID,NULL) == -1){
		perror("shmctl error");
		return -1;
	}
	del_sem(semid);
	return 0;
}