main.c 

#include "mysemop.h"
#include <stdlib.h>
#include <stdio.h>
#include <signal.h>

int root_sem_id = 0;
int chopsticks_sem_id[5];

int main(int argc, char argv[])
{
	pid_t pid;
	
	pid_t chldpid[5];
	
	char ch;
	int i = 0;

	int room_sem_id = CreateSem(4);
	for (i = 0; i < 5; i++) {
		chopsticks_sem_id[i] = CreateSem(1);
	}

	for (i = 0; i < 5; i++) {
		pid = fork();
		if (pid < 0) {
			fprintf(stderr,"When fork philosopher %d Failed!n", i);
			exit(-1);
		}
		if (pid == 0) {
			while (1) {
				printf("Philopher %d is thinking,No disterb!n", i);
				sleep(1);

				Psem(room_sem_id);
				printf("Philopher %d is hungry,so he entered the room.n", i);

				Psem(chopsticks_sem_id[i]);
				printf("Philopher %d pick up left chopstickn", i);

				Psem(chopsticks_sem_id[(i + 1) % 5]);
				printf("Philopher %d pick up right chopstickn", i);

				printf("Philopher %d begins to eat!n", i);
				sleep(5 - i);

				printf("Philopher %d ends to eat!n", i);
				Vsem(chopsticks_sem_id[(i + 1) % 5]);

				printf("Philopher %d put down right chopstickn", i);
				Vsem(chopsticks_sem_id[i]);

				printf("Philopher %d put down left chopstickn", i);
				Vsem(room_sem_id);

				printf("Philopher %d left the room!n",i);
				printf("Philopher %d begins thinking!n",i);
				sleep(1);
			}
		} else 
		{
			
			chldpid[i] = pid;
		
		}
	}
	
	do 
	{
		
		ch = getchar();
		
			if (ch == 'q')
		
			{
			
				for (i = 0; i < 5; i++)
				
					kill(chldpid[i], SIGTERM);
		
			}
	
	} while (ch != 'q');
}

mysemop.c

#include "mysemop.h"

int CreateSem(int value)
{
	int sem_id;
	sem_id = semget(IPC_PRIVATE, 1, 0666 | IPC_CREAT);
	if (sem_id == -1) return -1;
	if (SetSemValue(sem_id, value) == 0) return -1;
	return sem_id;
}

int SetSemValue(int sem_id, int value)
{
	if(semctl(sem_id, 0, SETVAL, value) == -1) return 0;
	return 1;
}

void DeleteSem(int sem_id)
{
	if(semctl(sem_id, 0, IPC_RMID) == -1)
		fprintf(stderr, "Failed to delete semaphoren");
}

int Psem(int sem_id)
{
	struct sembuf sem_b;
	sem_b.sem_num = 0;
	sem_b.sem_op = -1;
	sem_b.sem_flg = SEM_UNDO;
	if(semop(sem_id,&sem_b,1) == -1){
		fprintf(stderr, "P failedn");
		return 0;
	}
	return 1;
}

int Vsem(int sem_id)
{
	struct sembuf sem_b;
	sem_b.sem_num = 0;
	sem_b.sem_op =  1;
	sem_b.sem_flg = SEM_UNDO;
	if(semop(sem_id,&sem_b,1) == -1){
		fprintf(stderr, "V failedn");
		return 0;
	}
	return 1;
}

mysemop.h 

#ifndef MYSEMOP_H
#define MYSEMOP_H

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>

#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <errno.h>
#include <fcntl.h>

int CreateSem(int value);
int SetSemValue(int sem_id, int value);
void DeleteSem(int sem_id);
int Psem(int sem_id);
int Vsem(int sem_id);

#endif

在Linux命令行下执行：

mkdir exp
vi main.c
vi mysemop.c
vi mysemop.h
gcc main.c mysemop.c -o main
./main

实验结果：

简洁版的main.c也可以这样写：

#include<stdio.h>
#include<stdlib.h>
#include<signal.h>
#include"mysemop.h"
#define c_num 5
#define p_num 5
int main()
{
   int i;
   char c;
   int room;
   int chop_sem[c_num];
   room=CreateSem(c_num-1);
   for( i=0;i<c_num;i++)
    chop_sem[i]=CreateSem(1);

   pid_t pids[p_num];
   pid_t pid;
   for(i=0;i<p_num;i++)
   {
     pid=fork();
     if(pid<0)
       printf("error..n");
     else if(pid>0)
       pids[i]=pid;
     else if(pid==0)
     {
        while(1)
        {
          printf("thinking...n ");
          sleep(1);
          Psem(room);
          Psem(chop_sem[i]);
          Psem(chop_sem[(i+1)%5]);
          printf("%d is eating ...n",i);
          sleep(5-i);
          Vsem(chop_sem[(i+1)%5]);
          Vsem(chop_sem[i]);
          Vsem(room);
          printf("thinking...n");

        }

      }
   }
  
    do{
       c=getchar();
       if(c=='q')
       {
         for( i=0;i<p_num;i++)
            kill(pids[i],9);
       }
    }while(c!='q');

}