(PHP 4, PHP 5, PHP 7, PHP 8)
sem_release — Release a semaphore
sem_release() releases the semaphore if it is currently acquired by the calling process, otherwise a warning is generated.
After releasing the semaphore, sem_acquire() may be called to re-acquire it.
   成功时返回 true, 或者在失败时返回 false。
  
| 版本 | 说明 | 
|---|---|
| 8.0.0 | semaphoreexpects a SysvSemaphore
        instance now; previously, a resource was expected. | 
