philosopher5.c

改进的哲学家问题

/*在本次实验中，为了模拟算法应用的环境，将每个phiolosopher左右的两把叉子作为一个资源对待,且使用书上时间戳机制*/
#include "philosopher5.h"
void philosopher(int i)
{
printf("myID(%d) = %d\n",myID,getpid());
while(1)
	{
	think(i);
	take_fork(i);
	eat(i);
	put_fork(i);
	}
}

main()
{
int 	i;
pid_t	pid;

initforks();
for(i = 0; i < N; i++) 
{
      if( (pid = fork()) < 0)
			err_sys("fork error");
	  else
	  {
		if( (shmptr = (char*) shmat(shmid,(char*)0,0) ) ==(char*)-1)
	           {
			perror("get mermory shmat in child");
			exit(4);
	           }
		pids = (struct PID*)shmptr;
		if(pid == 0)	/*in child*/
		  {
			myID = i;
			init_child();
			sleep(2);
			philosopher(i);
			exit(1);
		  }
 		else	pids->P[i] = pid;
	}
}
wait(0);
}