What is the main difference between require() and require_once()?

Web Development
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#1

What is the main difference between require() and require_once()?

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#2

The main difference between require() and require_once() function is that require() function will include the file irrespective of whether the file is already included or not whereas require_once() function will check whether the file is already included or not, if it is already included then it won’t include the file.

#3

Difference between require() and require_once(): require() includes and evaluates a specific file, while require_once() does that only if it has not been included before (on the same page).

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.

Difference between require() and include() is that require() produces a FATAL ERROR if the file you want to include is not found, while include() only produces a WARNING.

There is also include_once() which is the same as include(), but the difference between them is the same as the difference between require() and require_once().