#include <sys/mman.h>
#include <stdio.h>
#include <unistd.h>
#include <time.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <stdio.h> //支持 printf
#include <sys/shm.h> //支持 shmget shmat 等
#include <sys/sem.h> //支持 semget
#include <stdlib.h> //支持 exit
#define MAX_PRODUCTS 10
struct sembuf buf;
int down(int sem_id)
{
buf.sem_num = 0;
buf.sem_op = -1;
buf.sem_flg = SEM_UNDO;
if (semop(sem_id, &buf, 1) == -1)
{
perror("Down failed!/n");
return 0;
}
return 1;
}
int up(int sem_id)
{
buf.sem_num = 0;
buf.sem_op = 1;
buf.sem_flg = SEM_UNDO;
if (semop(sem_id, &buf, 1) == -1)
{
perror("Up failed!/n");
return 0;
}
