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This article Xiaobian for you to introduce in detail "what is the concept of php semaphores and shared memory", the content is detailed, the steps are clear, and the details are handled properly. I hope this article "what is the concept of php semaphores and shared memory" can help you solve your doubts.

Description

1. Semaphore: an atomic operation provided by the system, a number of signals, and only one process can operate.

A process obtains a signal and must be released by the process.

2. Shared memory: a common memory area opened by the system in memory, which can be accessed by any process.

Multiple processes can access the area at the same time, and the memory area needs to be locked or signaled in order to ensure the consistency of the data.

Example

Echo "parent progress pid: {$parentPid}\ n"; $childList = array (); / / create shared memory, create semaphores, define shared key$shm_id = ftok (_ _ FILE__,'m'); $sem_id = ftok (_ _ FILE__,'s'); $shareMemory = shm_attach ($shm_id); $signal = sem_get ($sem_id); const SHARE_KEY = 1tactic / producer function producer () {global $shareMemory; global $signal $pid = posix_getpid (); $repeatNum = 5; for ($I = 1; $I 0) {unset ($childList [$childPid]);}} / / release shared memory and semaphore shm_remove ($shareMemory); sem_remove ($signal); echo "({$parentPid}) main progress end!\ n" After reading this, the article "what is the concept of php semaphores and shared memory" has been introduced. If you want to master the knowledge of this article, you still need to practice and use it to understand it. If you want to know more about related articles, welcome to follow the industry information channel.

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