xtd（进程通信）.c

一个简单的关于LINUX下的进程间通讯的演示,使用的是信号量.适合初学编程的同学一起学习!

#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include<string.h>
#include<time.h>
#include<errno.h>
#include<sys/types.h>
#include<sys/ipc.h>
#include<sys/sem.h>
#include<sys/wait.h>

static int w_time[]={7,6,5,4,3,2,1};            //进程的运行时间
static int semid=-1;                        //信号量集的IPC ID
                                        
                                        //定义要执行的对信号量的等待和通知操作    
static struct sembuf sops[]={
       	{0,1,0},{1,1,0},{0,-1,0},{2,1,0},{3,1,0},{1,-1,0},{4,1,0},{2,-1,0},{5,1,0},{3,-1,0},{6,1,0},{4,-1,0},{7,1,0},{5,-1,0},{6,-1,0},{7,-1,0}};
                                        //进程列表:
static struct{
	char *name;
	pid_t PID;
}process[]={{"s1",0},{"s2",0},{"s3",0},{"s4",0},{"s5",0},{"s6",0},{"s7",0}};

static void WorkTime(int processx,time_t t0)
{
	char *name=process[processx].name;
	pid_t pid=getpid();
	time_t tn;                          //末时间
	int z;
	if(processx==0)
	     {	
		for(;;)
		{  time(&tn);		
		  if(tn-t0>=w_time[processx])
		   {     printf("Process %s is working!\n",name);
			printf("Process %s has done!\n",name);
			z=semop(semid,&sops[0],1);if(z==-1){perror("semop()");exit(13);}
		        z=semop(semid,&sops[1],1);if(z==-1){perror("semop()");exit(13);}	
			
			return;	
		   }
		}	
	     }	
	else if(processx==1)
	     {  
		for(;;)
		{  time(&tn);
		   if(tn-t0>=w_time[processx])
		   {    z=semop(semid,&sops[2],1);if(z==-1){perror("semop()");exit(13);}
			 printf("Process %s is working!\n",name);printf("Process %s has done!\n",name);
			z=semop(semid,&sops[3],1);if(z==-1){perror("semop()");exit(13);}
		        z=semop(semid,&sops[4],1);if(z==-1){perror("semop()");exit(13);}	
			
			return;	
		   }
		}			  
	     }
	else if(processx==2)
	     {  
		for(;;)
		{  time(&tn);
		   if(tn-t0>=w_time[processx])
		   {    z=semop(semid,&sops[5],1);if(z==-1){perror("semop()");exit(13);}
			 printf("Process %s is working!\n",name);printf("Process %s has done!\n",name);
			z=semop(semid,&sops[6],1);if(z==-1){perror("semop()");exit(13);}	
			
			return;	
		   }
		}		
	     }	
	else if(processx==3)
	     {  
		for(;;)
		{  time(&tn);
   		  if(tn-t0>=w_time[processx])
		   {    z=semop(semid,&sops[7],1);if(z==-1){perror("semop()");exit(13);}
			 printf("Process %s is working!\n",name);printf("Process %s has done!\n",name);
			z=semop(semid,&sops[8],1);if(z==-1){perror("semop()");exit(13);}	
			
			return;	
		   }
		}		
	     }
	else if(processx==4)
	     { 
		for(;;)
		{ time(&tn);
		  if(tn-t0>=w_time[processx])
		   {    z=semop(semid,&sops[9],1);if(z==-1){perror("semop()");exit(13);}
			 printf("Process %s is working!\n",name);printf("Process %s has done!\n",name);
			z=semop(semid,&sops[10],1);if(z==-1){perror("semop()");exit(13);}	
			
			return;	
		   }
		}		
	     }
	else if(processx==5)
	     {  
		for(;;)
		{   time(&tn);
		   if(tn-t0>=w_time[processx])
		   {    z=semop(semid,&sops[11],1);if(z==-1){perror("semop()");exit(13);}
			 printf("Process %s is working!\n",name);printf("Process %s has done!\n",name);
			z=semop(semid,&sops[12],1);if(z==-1){perror("semop()");exit(13);}	
			
			return;	
		   }
		}		
	     }
	else if(processx==6)
	     {  
		for(;;)
		{  time(&tn); 
		   if(tn-t0>=w_time[processx])
		   {    z=semop(semid,&sops[13],1);if(z==-1){perror("semop()");exit(13);}
			z=semop(semid,&sops[14],1);if(z==-1){perror("semop()");exit(13);}
			z=semop(semid,&sops[15],1);if(z==-1){perror("semop()");exit(13);}
			 printf("Process %s is working!\n",name);	
			printf("Process %s has done!\n",name);
			return;	
		   }
		}		
	     }				



}

main(int argc,char **argv)
{
	int z;                           //返回值
	int x;			       //进程的序号 
	time_t t0;                       //计算开始的时间 
	union semun {int val;struct semid_ds *buf;ushort *array;}semarg;
	static ushort i[]={
		0,0,0,0,0,0,0,0};            //信号量集的初值
	pid_t chPID;		       //记录进程的PID号
	int status;                       //记录进程结束的状态
	//创建无关键字私有信号量集
		semid=semget(IPC_PRIVATE,8,0600);
			if(semid==-1)            //创建失败 
			   {perror("semget()");exit(1);}
        //初始化信号量集
		semarg.array=i;
		z=semctl(semid,0,SETALL,semarg);
			if(z==-1)
			   {perror("semctl()");exit(1);}
        //记录初是时间
		time(&t0);
        //创建7个子进程
		for(x=0;x<7;x++)
		     {   printf("1\n");
			if(!(chPID=fork()))	//子进程执行的代码				
			    {WorkTime(x,t0);return 0;}			
			else if(chPID==(pid_t)(-1))
			    {perror("fork()");return;}	printf("2\n");
			process[x].PID=chPID;
		     }	
	//等待进程全部结束
		x=0;
		for(;x<7;)
		  {	chPID=wait(&status);
			for(x=0;x<7;x++)
			    if(process[x].PID==chPID)
				{process[x].PID=0;break;	}    
			for(x=0;x<7;x++)
			    if(process[x].PID!=0)break;
			     	
		  }
		printf("All process hads ending!");			
	z=semctl(semid,0,IPC_RMID,semarg);
	if(z==-1){perror("semctl(IPC_RMID)");exit(1);}	
	return 0;
}