作业

1> 使用三个程序来完成输出 ABCABCABCABCABC

#include<myhead.h>
#include"sem.h"
#define PAGE_SIZE 4096
int main(int argc, const char *argv[])
{
	int semid=create_sem(3);
	printf("semid=%d\n",semid);
	if(semid==-1)
	{
		perror("create_sem error");
		return -1;
	}
	key_t key=ftok("/",'k');
	if(key==-1)
	{
		perror("ftok error!\n");
		return -1;	
	}
	int shmid=shmget(key,PAGE_SIZE,IPC_CREAT|0664);
	if(shmid==-1)
		{
			perror("shmget error!\n");
			return -1;
		}

	char *shmaddress=(char *)shmat(shmid,NULL,0);
	if(shmaddress==(void *)-1)
	{
		perror("shmat error!\n");
		return -1;
	}
	//输出
	while(1)
	{
		P(semid,2);
		*shmaddress='C';
		printf("%c\n",*shmaddress);
		V(semid,0);
		sleep(1);
	}
	if(shmdt(shmaddress)==-1)
	{
		perror("shmdt error!\n");
		return -1;
	}
	if(shmctl(shmid,IPC_RMID,NULL)==-1)
	{
		perror("shmctl error!\n");
		return -1;

	}
	del_sem(semid);
	return 0;
}

#include<myhead.h>
#include"sem.h"
#define PAGE_SIZE 4096
int main(int argc, const char *argv[])
{
	int semid=create_sem(3);
	printf("semid=%d\n",semid);
	if(semid==-1)
	{
		perror("create_sem error");
		return -1;
	}
	key_t key=ftok("/",'k');
	if(key==-1)
	{
		perror("ftok error!\n");
		return -1;	
	}
	int shmid=shmget(key,PAGE_SIZE,IPC_CREAT|0664);
	if(shmid==-1)
		{
			perror("shmget error!\n");
			return -1;
		}

	char *shmaddress=(char *)shmat(shmid,NULL,0);
	if(shmaddress==(void *)-1)
	{
		perror("shmat error!\n");
		return -1;
	}
	//输出
	while(1)
	{
		P(semid,1);
		*shmaddress='B';
		printf("%c\n",*shmaddress);
		V(semid,2);
		sleep(1);
	}
	if(shmdt(shmaddress)==-1)
	{
		perror("shmdt error!\n");
		return -1;
	}
	if(shmctl(shmid,IPC_RMID,NULL)==-1)
	{
		perror("shmctl error!\n");
		return -1;

	}
	del_sem(semid);
	return 0;
}

#include<myhead.h>
#include"sem.h"
#define PAGE_SIZE 4096
int main(int argc, const char *argv[])
{
	int semid=create_sem(3);
	printf("semid=%d\n",semid);
	if(semid==-1)
	{
		perror("create_sem error");
		return -1;
	}
	key_t key=ftok("/",'k');
	if(key==-1)
	{
		perror("ftok error!\n");
		return -1;	
	}
	int shmid=shmget(key,PAGE_SIZE,IPC_CREAT|0664);
	if(shmid==-1)
		{
			perror("shmget error!\n");
			return -1;
		}

	char *shmaddress=(char *)shmat(shmid,NULL,0);
	if(shmaddress==(void *)-1)
	{
		perror("shmat error!\n");
		return -1;
	}
	//输出
	while(1)
	{
		P(semid,0);
		*shmaddress='A';
		printf("%c\n",*shmaddress);
		V(semid,1);
		sleep(3);
	}
	if(shmdt(shmaddress)==-1)
	{
		perror("shmdt error!\n");
		return -1;
	}
	if(shmctl(shmid,IPC_RMID,NULL)==-1)
	{
		perror("shmctl error!\n");
		return -1;

	}
	del_sem(semid);
	return 0;
}

2> 将共享内存和信号灯集完成两个进程间通信程序重新实现一下

#include<myhead.h>
#include"sem.h"
#define PAGE_SIZE 4096
int main(int argc, const char *argv[])
{
	//1.---信号灯集创建并初始化
	int semid=create_sem(2);
	//创建key
	key_t key=ftok("/",'k');
	if(key ==-1)
	{
		perror("ftok error!\n");
		return -1;
	}
	//使用key来创建共享内存段
	int shmid=shmget(key, PAGE_SIZE , IPC_CREAT|0664);
	if(shmid==-1)	
	{
		perror("shmget error");
		return -1;
	}
	printf("shmid %d\n",shmid);
	//映射共享内存段到用户空间
	char *addr=(char *)shmat(shmid,NULL,0);
	if(addr==(void*)-1)
	{
		perror("shmat error");
		return -1;
	}
	//使用共享内存段
	while(1)
	{

		//2.---P操作
		P(semid,1);
		printf("请输入》》》");
		fgets(addr,PAGE_SIZE,stdin);
		addr[strlen(addr)-1]='\0';
		//3.---v操作
		V(semid,0);
		if(strcmp(addr,"quit")==0)
		{
			break;
		}
	}
	//撤销映射
	if(shmdt(addr)==-1)
	{
		perror("shmdt error\n");
		return -1;
	}
	//删除共享内存段
	if(shmctl(shmid,IPC_RMID,NULL)==-1)
	{
		perror("shctl error\n");
		return -1;
	}

	//4.---信号灯集删除
	del_sem(semid);
	return 0;
}

#include<myhead.h>
#include"sem.h"
#define PAGE_SIZE 4096
int main(int argc, const char *argv[])
{
	//1.---信号灯集创建并初始化
	int semid=create_sem(2);
	//创建key
	key_t key=ftok("/",'k');
	if(key ==-1)
	{
		perror("ftok error!\n");
		return -1;
	}
	//使用key来打开共享内存段
	int shmid=shmget(key, PAGE_SIZE , IPC_CREAT|0664);
	if(shmid==-1)	
	{
		perror("shmget error");
		return -1;
	}
	printf("shmid %d\n",shmid);
	//映射共享内存段到用户空间
	char *addr=(char *)shmat(shmid,NULL,0);
	if(addr==(void*)-1)
	{
		perror("shmat error");
		return -1;
	}
	//使用共享内存段-读取
	while(1)
	{
		//2.---P操作
		P(semid,0);
		printf("共享内存段内内容->%s\n",addr);
		//3.---v操作
		V(semid,1);
		if(strcmp(addr,"quit")==0)
		{
			break;
		}
	}
	//撤销映射
	if(shmdt(addr)==-1)
	{
		perror("shmdt error\n");
		return -1;
	}
	//删除共享内存段
	if(shmctl(shmid,IPC_RMID,NULL)==-1)
	{
		perror("shctl error\n");
		return -1;
	}
	//4.---信号灯集删除
	del_sem(semid);
	return 0;
}