| 发表于：2007-12-04 17:23:273楼 得分:0 |
附个源代码，大家看看。
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <stdio.h>
#include <sys/shm.h>
#define key （key_t) 105
#define key2 （key_t) 108
#define max_buffer_size 10
union semun{
int val;
struct semid_ds *buf;
ushort *array;
};
typedef struct _tagsharebuffer{
int buffer[max_buffer_size];
int writer;
int reader;
}sharebuffer;
int main（)
{
int shmid;
char* shmptr;
sharebuffer* psharebuffer;
int product=0;
int semid;
struct sembuf mutex,empty,full;
int i;
if（（semid=semget（key,3,ipc_creat ¦0660))==-1)
{
printf（"semget error!\n");
return -1;
}
union semun arg[3];
arg[0].val=1;
arg[1].val=max_buffer_size;
arg[2].val=0;
for（i=0;i <3;i++)
semctl（semid,i,setval,arg[i]);
for（i=0;i <3;i++)
printf（"the semval（%d)=%d\n",i,semctl（semid,i,getval,null));
if（（shmid=shmget（ipc_private,sizeof（sharebuffer),0600)) <0)
{
printf（"shmget error!\n");
return -1;
}
if（（shmptr=（char*)shmat（shmid,0,0))==（void*)-1)
{
printf（"shmat error!\n");
return -1;
}
memset（（void*)shmptr,0,sizeof（sharebuffer));
psharebuffer=（sharebuffer*)shmptr;
int childpid=fork（);
if（childpid==-1)
{
printf（"create process error!");
return -1;
}
if（childpid==0)
{
while（1)
{
empty.sem_num=1;
empty.sem_op=-1;
empty.sem_flg=0;
semop（semid,&empty,1);
psharebuffer-> buffer[psharebuffer-> writer]=product;
for（i=0;i <3;i++)
printf（"the semval（%d)=%d\n",i,semctl（semid,i,getval,null));
printf（"produced the product into buffer[%d]=%d;\n",psharebuffer-> writer,product);
product++;
mutex.sem_num=0;
mutex.sem_op=-1;
mutex.sem_flg=0;
semop（semid,&mutex,1);
psharebuffer-> writer=（psharebuffer-> writer+1)%max_buffer_size;
mutex.sem_num=0;
mutex.sem_op=1;
mutex.sem_flg=0;
semop（semid,&mutex,1);
full.sem_num=2;
full.sem_op=1;
full.sem_flg=0;
semop（semid,&full,1);
sleep（1);
}
}
else
{
while（1)
{
sleep（5);
full.sem_num=2;
full.sem_op=-1;
full.sem_flg=0;
semop（semid,&full,1);
product=psharebuffer-> buffer[psharebuffer-> reader];
for（i=0;i <3;i++)
printf（"the semval（%d)=%d\n",i,semctl（semid,i,getval,null));
printf（"consumed the product from buffer[%d]=%d;\n",psharebuffer-> reader,product);
product--;
mutex.sem_num=0;
mutex.sem_op=-1;
mutex.sem_flg=0;
semop（semid,&mutex,1);
psharebuffer-> reader=（psharebuffer-> reader+1)%max_buffer_size;
mutex.sem_num=0;
mutex.sem_op=1;
mutex.sem_flg=0;
semop（semid,&mutex,1);
empty.sem_num=1;
empty.sem_op=1;
empty.sem_flg=0;
semop（semid,&empty,1);
}
}
return 0;
}
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