p-c.c

操作系统实验一到四 哈尔滨工业大学计算机学院的

#define __LIBRARY__
#include <unistd.h>
#include <stdio.h>

_syscall2(sem_t *,sem_open,const char *,name, unsigned int,value);
_syscall1(int ,sem_wait , sem_t *,sem);
_syscall1(int ,sem_post , sem_t *,sem);
_syscall1(int ,sem_unlink,const char *,name);
_syscall1(int ,pcinsert,int ,item);
_syscall0(int ,pcdelete);

#define NR_BUFFERS 10
#define NR_Produces 500
#define NR_Consumes 50

sem_t * mutex;
sem_t * empty;
sem_t * full;

void Producer(int nr_produces)
{
    int i;
    for(i=0; i<nr_produces; i++)
    {
	sleep(1);        
	sem_wait(empty);
        sem_wait(mutex);
	pcinsert(i);
        sem_post(mutex);
        sem_post(full);
    }
}

void Consumer(int nr_consumes)
{
    int i,item;
    for(i=0; i<nr_consumes; i++)
    {
        sleep(1);
	sem_wait(full);
        sem_wait(mutex);
        item=pcdelete();
	printf("%d : %d\n",getpid(),item);
	fflush(stdout);
        sem_post(mutex);
        sem_post(empty);
    }
}

int main()
{
    int i;
    
    mutex=sem_open("PCMutex", 1);
 
    empty=sem_open("PCEmpty", NR_BUFFERS);
   
    full=sem_open("PCFull", 0);
    
    if(!fork())
    {
      
	
	Producer(NR_Produces);
	exit(5);	
    }
    for(i=0;i<10;i++)
    {
	if(!fork()){
		
		
	    Consumer(NR_Consumes); exit (5);}
	} 
   
  
}