信号量
请大家帮分析下，信号量这么用对吗？加锁的话不应该资源减一吗？我看代码里这么用也没报错呢？

[code=C/C++][/code]

int kb_sem_lock()
{
int rv = 0;
struct sembuf operation[2];

operation[0].sem_num = 0;
operation[0].sem_op = 0;
operation[0].sem_flg = SEM_UNDO;
operation[1].sem_num = 0;
operation[1].sem_op = 1;
operation[1].sem_flg = SEM_UNDO;
rv = (semop(kb_sem_id, &operation[0], 2));
return rv;
}

int kb_sem_unlock()
{
struct sembuf operation[1];
int rv = 0;
operation[0].sem_num = 0;
operation[0].sem_op = -1;
operation[0].sem_flg = SEM_UNDO;

rv = semop(kb_sem_id, &operation[0], 1);
return rv;
}

------解决方案--------------------
用了两个信号灯？

对于简单的同步，一般使用单个信号灯就行了
初值为1，加锁时-1，解锁时+1