This only succeeds if another thread does not already have the lock, in which case the current thread is blocked.

只有在其他线程不拥有锁的情况下才会成功，如果其他线程拥有锁，当前线程就被阻塞。

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Another special case of locking is the need to lock something where currently no database row exists.

锁定的另一个特例是需要锁定当前数据库行中不存在的项目。

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In this case, a logical lock (not a physical database lock) is used to flag that a row is in use for a long-term duration.

在本方案中，通过逻辑锁(而不是物理锁)来对在较长时间中使用的数据行进行标记。

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When folded down, the antennas not only lock the case and but also seal off its various ports.

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Another problem is the case of all-included hotels that lock-up the tourist without letting him to get to know the environs.

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One managed to fit the lock-hacking tool into an iPhone case.

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