php php中require和require_once的区别
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the differences between require and require_once in php
提问by Ravi Mane
the difference between require and require_once. I just want to know the difference rather than Warning and Fatal Error in php.
require 和 require_once 的区别。我只想知道区别而不是 php 中的警告和致命错误。
回答by Neat
require()includes and evaluates a specific file, while require_once()does that only if it has not been included before (on the same page).
require()包含并评估特定文件，而require_once()仅在之前（在同一页面上）未包含该文件时才执行此操作。
So, require_once()is recommended to use when you want to include a file where you have a lot of functions for example. This way you make sure you don't include the file more times and you will not get the "function re-declared" error.
因此，例如，require_once()当您要包含具有很多功能的文件时，建议使用。通过这种方式，您可以确保不会多次包含该文件，并且不会出现“重新声明函数”错误。
