Shulou(Shulou.com)06/01 Report--

This article gives you a detailed introduction to the flock function in php. Most of the examples can be applied to work, so I can share them for you as a reference. Let's follow the editor and have a look.

Bool flock (resource $handle, int $operation [, int & $wouldblock])

Flock () allows you to execute a simple read / write model that can be used on any platform (including most Unix derivatives and windows)

Before PHP 5.3.2, the lock was released by fclose () (called automatically at the end of the script), and now needs to be unlocked manually

Operation

1.LOCK_SH acquires a shared lock (read program)

2.LOCK_EX acquires exclusive lock (written program)

3.LOCK_UN releases locks (whether shared or exclusive)

4.LOCK_NB does not block when flock () locks

Example 1: Rana A uses exclusive locks to write files, B reads files, blocking

A.php

B.php

Execute a.php first, then b.php

An acquires the exclusive lock, b can only wait and wait for a to unlock the lock before executing b, blocking

Example 2, both of them use shared locks and do not block

A.php

B.php

Execute a.php first, then b.php

B does not need to wait for a to finish execution to output the contents of the file, non-blocking

In example 3, all of the files are written with exclusive locks, blocking

A.php

B.php

Execute a.php first, then b.php

B needs to wait for a to finish execution before writing data, blocking

Instance 4:LOCK_NB does not block or wait when it is locked

A.php

B.php

Execute a.php first, then b.php

B can not get the exclusive lock, do not need to wait for a to finish execution, but directly return to get no lock prompt, non-blocking

Summary:

Using the shared lock LOCK_SH, if it is a read, you do not need to wait, but if it is a write, you need to wait for the read to complete.

With the exclusive lock LOCK_EX, you have to wait for both writes / reads.

LOCK_UN, whether using shared / read preemptive locks, needs to be unlocked after use.

LOCK_NB, when locked, does not block, but prompts for locking.

After reading the above, have you mastered how to use the flock function? If you want to learn more skills or want to know more about it, you are welcome to follow the industry information channel, thank you for reading!

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