As shown in the picture, when I run two scripts at the same time, why can the second script write to the file immediately? Isn’t the file locked in the first script?
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As shown in the picture, when I run two scripts at the same time, why can the second script write to the file immediately? Isn’t the file locked in the first script?
PHP reading and writing files are locked. For details, please refer to this http://www.jb51.net/article/81246.htm
Your second fwrite is operated without applying for the exclusive lock LOCK_EX before, and of course it will be written.
You must apply for LOCK_EX before both fwrites, so that it can have a locking effect.
<code>foo1.php: <?php header('Content-Type: text/plain; charset=utf-8'); if(file_exists('arr.php')) { $arr = require 'arr.php'; //先require后fopen } else { file_put_contents('arr.php','<?php return array();'); } $fp = fopen('arr.php', 'r+'); //读写方式打开,将文件指针指向文件头 if(flock($fp,LOCK_EX)) { //阻塞到获取排它锁 $arr['name'] = __FILE__; ftruncate($fp, 0); //截断文件 fwrite($fp,'<?php return '.var_export($arr, true).';'); var_export($arr); fflush($fp); //在释放锁之前刷新输出 sleep(10); //睡眠10秒,在此期间访问foo2.php将被阻塞 flock($fp, LOCK_UN); //释放锁定 } fclose($fp); foo2.php: <?php header('Content-Type: text/plain; charset=utf-8'); $arr = require 'arr.php'; $fp = fopen('arr.php', 'r+'); if(flock($fp,LOCK_EX)) { $arr['name'] = __FILE__; ftruncate($fp, 0); fwrite($fp,'<?php return '.var_export($arr, true).';'); var_export($arr); fflush($fp); flock($fp, LOCK_UN); } fclose($fp);</code></code>

What’s still popular is the ease of use, flexibility and a strong ecosystem. 1) Ease of use and simple syntax make it the first choice for beginners. 2) Closely integrated with web development, excellent interaction with HTTP requests and database. 3) The huge ecosystem provides a wealth of tools and libraries. 4) Active community and open source nature adapts them to new needs and technology trends.

PHP and Python are both high-level programming languages that are widely used in web development, data processing and automation tasks. 1.PHP is often used to build dynamic websites and content management systems, while Python is often used to build web frameworks and data science. 2.PHP uses echo to output content, Python uses print. 3. Both support object-oriented programming, but the syntax and keywords are different. 4. PHP supports weak type conversion, while Python is more stringent. 5. PHP performance optimization includes using OPcache and asynchronous programming, while Python uses cProfile and asynchronous programming.

PHP is mainly procedural programming, but also supports object-oriented programming (OOP); Python supports a variety of paradigms, including OOP, functional and procedural programming. PHP is suitable for web development, and Python is suitable for a variety of applications such as data analysis and machine learning.

PHP originated in 1994 and was developed by RasmusLerdorf. It was originally used to track website visitors and gradually evolved into a server-side scripting language and was widely used in web development. Python was developed by Guidovan Rossum in the late 1980s and was first released in 1991. It emphasizes code readability and simplicity, and is suitable for scientific computing, data analysis and other fields.

PHP is suitable for web development and rapid prototyping, and Python is suitable for data science and machine learning. 1.PHP is used for dynamic web development, with simple syntax and suitable for rapid development. 2. Python has concise syntax, is suitable for multiple fields, and has a strong library ecosystem.

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PHPhassignificantlyimpactedwebdevelopmentandextendsbeyondit.1)ItpowersmajorplatformslikeWordPressandexcelsindatabaseinteractions.2)PHP'sadaptabilityallowsittoscaleforlargeapplicationsusingframeworkslikeLaravel.3)Beyondweb,PHPisusedincommand-linescrip

PHP type prompts to improve code quality and readability. 1) Scalar type tips: Since PHP7.0, basic data types are allowed to be specified in function parameters, such as int, float, etc. 2) Return type prompt: Ensure the consistency of the function return value type. 3) Union type prompt: Since PHP8.0, multiple types are allowed to be specified in function parameters or return values. 4) Nullable type prompt: Allows to include null values and handle functions that may return null values.


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